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Homogenizer를 사용한 W/O 에멀젼법하에 나노크기 알루미나 분체 제조 가능성 평가
이융 ( Yoong Lee ),함영민 ( Yeong Min Hahm ) 한국공업화학회 2010 공업화학 Vol.21 No.5
W/O 에멀젼법하에 homogenizer를 사용하여 α-알루미나 분체 제조 시 O:W 부피비, 교반속도, 계면활성제 사용량과 조성 및 종류 등의 변화에 의하여 분체의 입자형상, 응집성, 평균입경과 입도분포 등의 변화를 분석하였다. 계면활성제는 비이온 계면활성제가 사용되었고 단일 및 혼합계면활성제로는 SP80 및 [SP80 & TW80]을 사용하였고 보조계면활성제로는 n-부탄올을 사용하였다. SP80을 사용하였을 경우, 분체의 입자형상은 구형에 근접하였고 평균입경은 주어진 O:W 부피비 변화 및 16000 rpm 이상의 교반속도에서 큰 차이를 보이지 않았다. [SP80 & TW80]을 사용하였을 경우, 구형에 가까운 분체의 입자간 응집 및 합체현상은 HLBm = 5일 때 낮았고 평균입경은 단일계면활성제를 사용하였을 때 비하여 다소 감소하였다. HLBm = 5인 [SP80 & TW80]와 함께 0.1 vol% n-부탄올을 사용하였을 경우, 입자간 응집성이 상대적으로 낮고 나노크기의 입도를 갖는 분체 분율을 증가시킬 수 있었다. Under W/O emulsion method using a homogenizer, α-alumina powder was prepared to evaluate the effects of experimental conditions on its properties, such as particle shape, extent of aggregation, average particle size and distribution. The experimental parameters were the change of type, quantity and composition of emulsifiers as well as the change of O:W volumetric ratio and agitation rate. As results, in the case of the use of single surfactant of SP80, sphere-like particles could be prepared and the average particle size was hardly affected by the agitation speed more than 16000 rpm regardless of SP80 quantity used. When the extent of aggregation among sphere-like particles prepared using HLBm = 5 of [SP80 & TW80] was compared with that prepared using SP80 at the same vol% surfactant and agitation speed, the former showed more or less low aggregation phenomena and average particle size was slightly reduced. In addition, the fraction of nano-sized particles with low aggregation was increased by the use of 0.1 vol% n-butanol, as a co-surfactant, with HLBm = 5 of [SP80 & TW80].
탄성중합체 함유량 변화에 따른 폴리아미드-6,6 / 탄성중합체 블랜드물의 특성
이융(Yoong Lee),이창우(Chang Woo Lee),차윤호(Yoon Ho Cha),함영민(Yeong Min Hahm) 한국고무학회 1999 엘라스토머 및 콤포지트 Vol.34 No.1
N/A In this study, binary polyamide 6,6(PA 6,6)/ethylene-propylene rubber(EPM) or EPM-g-maleic anhydride(EPM-g-MA) blends and ternary PA 6,6/EPM/EPM-g-MA blends with various elastomer content were prepared in order to investigate the degree of influence of elastomer content and average particle size, morphology, and distribution of dispersed elastomer on mechanical and thermal properties of blends. According to the results, notched Izod impact strength and relative crystallinity of binary blends modified with EPM-AMA as well as average particle size and distribution of dispersed elastomer in such blends were more improved than those of binary blends modified with EPM. Notched Izod impact strength of blend whose composition ratio(wt%) was 70:30(PA 6,6: EPM-g-MA) was the highest among the binary PA 6,6/EPM-g-MA blends. The impact strength was increased by 25 times and its relative crystallinity was increased by 7 times when compared with those of polyamide 6,6. In the case of ternary PA 6,6/EPM/EPM-g-MA blend of which composition ratio was 70 : 15 : 15(PA 6,6 : EPM : EPM-g-MA), the elastomer was finely distributed with the average particle size of 0.56㎛. The Izod impact strength of this blend was the highest of all blends prepared with different elastomer content.
슬러리 기포탑 반응기에서 침강성 탄산칼슘의 모폴로지에 대한 조업변수들의 영향
황정우(Jung Woo Hwang),이융(Yoong Lee),이동현(Dong Hyun Lee) 한국청정기술학회 2010 청정기술 Vol.16 No.2
슬러리 기포탑을 이용하여 수산화칼슘 농도(0.16~0.64 wt%), 계면활성제 농도(2~16 wt%), 총 부피유량(3~6 L/min) 및 CO₂ 유량의 부피분율(0.3~0.6)이 탄산칼슘의 morphology, 결정구조, 입자의 크기, 입자 간의 응집화, 비표면적에 미치는 영향을 알아보았다. 실험에 사용한 반응기는 높이가 1.0 m이고 직경이 0.11m, 그리고 중앙에는 직경 4 cm인 튜브가 들어있는 슬러리 기포탑이다. 실험에 사용한 음이온 계면활성제 Dispex N40은 탄산칼슘 합성에 있어 반응 속도에 영향을 주어 반응 종결 시간을 감소시켰다. Dispex N40의 농도가 2 wt%일 때 수산화칼슘의 포화농도인 0.16 wt%에서 이산화탄소의 유량에 따른 침강성 탄산칼슘의 morphology를 살펴보면 반응 속도가 증가할수록 결정의 형태는 단일 결정으로 존재하는 입자들이 많아졌다. Dispex N40은 탄산칼슘의 crystal의 성장과 입자와 입자간의 응집 현상에 영향을 주어 탄산칼슘의 평균 입도를 변화시켰다. 또한 0.9 L/min CO₂ 유량에서 수산화칼슘의 농도가 0.64 wt%일 때 2 wt%의 계면활성제 첨가로 인해 비표면적을 35m²/g에서 44m²/g로 크게 증가시켰다. Effects of Ca(OH)₂ concentration (0.16~0.64 wt%), surfactant concentration (2~16 wt%), total volumetric flow rate (3~6 L/min) and CO₂ volume fraction (0.3~0.6) on morphology, crystal structure, mean particle diameter, aggregation and specific surface area of the precipitated CaCO₃ were investigated in the slurry bubble column reactor. Experiments were carried out in acrylic reactor (0.11 m-ID×1.0 m-high) with a internal tube (0.04 m-ID×1.0 m-high). The reaction time of CaCO₃ synthesis decreased with adding Dispex N40 of the anionic surfactant. The reaction rate of Ca(OH)₂ increased with increasing the volumetric flow rate of CO₂. From SEM images, the single crystal of CaCO₃ increased with increasing the reaction rate in the saturated concentration of Ca(OH)₂ (0.16 wt %) and the concentration of Dispex N40 (2 wt%). The mean particle size of CaCO₃ varied with adding Dispex N40. In addition, the specific surface area of CaCO₃ increased with adding of surfactant (2 wt%) from 35 m²/g to 44 m²/g at the volumetric flow rate of CO₂ (0.9 L/min) and the concentration of Ca(OH)₂ (0.64 wt %).
파라핀 오일을 이용한 W/O 에멀젼법하에 구형 γ-알루미나 분체 제조시 유화제 종류 및 조성변화의 영향
이융,이상우,이창일,함영민 한국공업화학회 2002 응용화학 Vol.6 No.2
In this work, the average particle size, the degree of monodispersity of particle size and the morphology of v-A1_2O_3 powder were investigated by changing the type and composition of emulsifiers under 0/W emulsion method. Water phase(W) was aq. v-A1_2O_3 sol of pH=3 and oil phase(O) was paraffin oil containing diverse main surfactants and[or] cosurfactants, which were sp8O, tw80, n-butanol, n-octanol and n-dodecanol. The mixing rate & mixing time and the O:W volumetric ratio to form emulsion were 2,000rpm & lhr and 8:1, respectively. As results, the morphology of v-A1_2O_3 powder prepared under all conditions was spherical form and the min. average particle size, 0.56㎛, was obtained when mixed surfactants of 2vol.%[sp80 & tw8O] of HLBm=5 were used. and the max. monodispersity of particle size, 1.06, was achieved when 0.4vol.%n-butanol, as a cosurfactant, was used with 2vol.%[sp80 & tw8O] of HLBm=5.