혼합계면활성제를 이용한 W/O 에멀젼법하에 응집현상이 제어된 구형의 알루미나 미분체의 제조

이융 ( Lee Yung ),함영민 ( Ham Yeong Min ) 한국공업화학회 2003 공업화학 Vol.14 No.8

리튬이 삽입된 흑연 층간화합물로부터 팽창흑연의 새로운 제조방법과 응용에 대하여 열처리 온도에 대한 팽창화 부피, 시트(sheet)상 흑연의 기계적 특성 및 원유의 흡유량 등을 연구하였다. 생성물의 팽창 부피는 Li 양과 열처리 온도의 증가와 함께 증가함을 보였다. 팽창흑연의 부피와 pH 농도 등의 두 가지 중요한 요소는 시트(sheet) 생성물의 품질과 기계적 특성에 영향을 주었다. 뿐만 아니라 여러 가지 Li 양과 제조 온도에 따른 팽창흑연에 원유의 흡착거동이 역시 연구되었다. 이들 연구 결과로부터, Li_(30)-EG850과 Li_(30)-EG900 팽창흑연의 최대 흡유량은 팽창흑연 1 g당 원유 69~81 g으로 상당히 높게 나타났다. 마지막으로, 시간에 의존하여 Li_(30)-EG의 최대 흡유량은 열처리 온도와 관련하여 흡유 시간의 증가와 함께 증가하였다. Effects of the type and the composition of surfactant mixtures on morphology. average particle size and particle size distribution of a-alumina prepared by W/O emulsion method including combustion method were investigated. SP80 was used as a main surfactant, [SP80 & TW20] as well as [SP80 & TW80] as surfactant mixtures. As results, the above properties of alumina power prepared by using low mechanical agitation speed, 500 rpm. were not affected remarkably by the variation of type and composition of mixed-surfactants regardless of O : W volumetric ratio at fixed content of surfactant. However, under the conditions of 1 vol.% and 2 vol.% [SP80 & TW20] or [SP80 & TW80] of HLB_(m) = 5, O:W = 8 : 1 and 2000 rpm, the average particle size became much smaller and the range of particle size distribution was narrow in comparison with those obtained from the usage of single surfactant, SP80. These effects were enhanced when [SP80 & TW80] were used instead of [ST80 & TW20]. And also, under 4000 rpm, severe coalescence phenomena among alumina powder prepared by using 2.5 vol.% SP80 for O : W = 8 : 1.5 were reduced drastically by using 2.5 vol.%[SP80 & TW80] of HLB, -5.

콜로이드 응집법으로 제조된 다공성 구형 실리카의 액체 크로마토그래피 컬럼 충진물로의 응용

이창일 ( Lee Chang Il ),이융 ( Lee Yung ),함영민 ( Ham Yeong Min ) 한국공업화학회 2003 공업화학 Vol.14 No.6

콜로이드 응집법을 이용하여 다공성 구형 실리카를 제조하고 액체 크로마토그래피의 컬럼 충진물로서의 응용에 관한 연구를 수행하였다. 다공성 구형 실리카의 표면은 역상 액체 크로마토그래피의 컬럼 충진물로서 응용하기 위하여 여러 가지 실란 화합물로 개질되었다. 실리카의 표면개질 결과, 실란화합물이 가지고 있는 작용기가 클로로기일 경우에 에톡시기인 경우보다 높은 소수화도를 보였으며, 알킬기의 사슬길이에 따라 carbon loading량이 증가하였다. 또한 표면 처리 시간의 증가에 따라서 보다 높은 소수화도 및 carbon loading을 나타내었으며, 적절한 처리시간은 약 48 h이었다. 표면 개질된 실리카를 컬럼에 충진하여 방향족 화합물의 분리 거동을 알아보기 위하여 액체 크로마토그래피에 적용한 결과, 상용 실리카 컬럼과 동일한 분리 거동을 보여 주었으며 실리카 표면의 end-capping을 통하여 peak의 대칭성을 증가시키고, 이동상으로 사용되는 혼합 용매의 조성과 이동상의 속도를 조절하여 최적의 분리조건을 결정할 수 있었다. The object of this study was production of porous spherical silica by a colloid aggregation method and its application as column packing material of liquid chromatography. The surface of porous spherical silica was modified with various silane coupling agents in order to apply the produced porous spherical silica as column packing material of reversed phase liquid chromatography. As a result of surface modifying, it was found that hydrophobicity was higher when the functional group was a chloro group rather than an ethoxy group. The amount of carbon loading increased proportional to the chain length of alkyl group. Moreover. as the surface modification time increased, the hydrophobicity and carbon loading increased. The appropriate time for surface modification was 48 hours. As a result of packing the column with the surface modified silica and applying liquid chromatography to examine the separation behavior of aromatic compounds, it showed the same separation behavior as a commercial packing and the peak symmetry was increased through end-capping. The optimum separation condition was determined in view of the composition of mixed solvent and flow rate control.

콜로이드 응집법에 의한 구형 실리카 분체 제조시 입자 크기 제어에 관한 연구

이상우 ( Lee Sang U ),이창일 ( Lee Chang Il ),이융 ( Lee Yung ),함영민 ( Ham Yeong Min ) 한국공업화학회 2003 공업화학 Vol.14 No.7

Colloidal silica를 urea 및 formaldehyde의 중합공정을 통하여 얻어지는 urea-formaldehyde resin과 함께 응집시킨 후 유기물의 제거과정을 통하여 구형 실리카 분체를 제조하였다. 구형 실리카 분체 제조시 colloidal silica 및 formaldehyde의 농도와 반응물의 pH, 산의 종류, 용매의 부피 및 혼합용매의 종류를 변화시켜 입자크기에 대한 영향을 조사하였다. 열중량 분석 및 FT-IR 분석을 통하여 응집체 중의 유기물의 열분해 거동 및 순수 실리카의 특성 피크를 확인하고, SEM분석을 통해 입자의 형상 및 크기를 측정하여 평균입경과 균일도(monodispersity)를 분석하였으며, BET법을 이용하여 실리카 입자의 비표면적, 기공크기 및 기공분포를 측정하였다. 실험결과, colloidal silica의 농도가 높아질수록 입자 크기가 증가하는 경향을 관찰하였으며, formaldehyde의 농도를 변화시켰을 경우 urea와 formaldehyde의 몰비가 1:1~1:1.2일 경우 가장 단분산된 실리카 분체를 제조할 수 있었다. 또한, pH가 낮아질수록 입자크기가 작아지고 입도분포의 균일도가 증가되는 경향을 나타내었다. Spherical silica powder was fabricated by using colloid aggregation method which involves polymerization of urea with formaldehyde. This aggregation process includes formation of urea-formaldehyde resin (UF resin) and growth of silica-UF resin aggregates. After the aggregation process, the UF resin could be burned off to form a pure spherical silica powder The effect of concentration of colloidal silica and formaldehyde. pH of reactants, type of acid catalysts, and solvents on particle size of spherical silica powder was investigated. The TGA traces and FT-IR spectra were collected to examine decomposition temperature of UF resin and the bond structure of silica Particle shape, size, and monodispersity was analyzed by SEM. Specific surface area, pore diameter and pore distribution were calculated from N₂ Adsorption using BET method. It was found that increase in the concentration of colloidal silica increased average particle size of silica powder. Optimum molar ratio of urea(fixed condition) and formaldehyde for preparing monodispersed silica powder was 1:1-1:1.2. In addition decrease in pH decreased average particle size of silica powder and increased monodispersity of silica powder.

垂直棒을 充塡한 氣泡塔에서 混合特性에 關한 硏究

姜京熙,咸榮敏 단국대학교 1984 論文集 Vol.18 No.-

The axial mixing characteristic were investigaved in a cocurrent bubblecolumn containing vertical rods. The gas hold-up was determined by the bed expansion measuring technique. An impulse response technique was employed to obtain RTD-curves. The RTD-curves were analysed for determination of the mean residence time and the axial disperson coefficient. The gas hold-up was not affected by the ncrease of the number of rods, but there were increasing tendencies of the mean residence time and the axial dipersion coefficient with the increase of she number of rods. Also axial dispersion coefficient was found to increase with superficial liquid and gas velocity. The data weve obtained in the approximate range of gas velocity of 3 ㎝/sec to 10 ㎝/sec and liquid velocity of 0.2 ㎝/sec to 0.9 ㎝/sec.

졸 - 겔법에 의한 구형 Mullite 미립자 제조

이정혜,이창우,장윤호,함영민 한국공업화학회 1998 응용화학 Vol.2 No.2

The spherical mullite fine powder was fabricated by sol-gel method in order to let it have highly functional property. By using ASB[Aluminium tri-sec butoxide] and TEOS[Tetraethyl orthosilicate] as precursors, n-octanol as solvents and acetonitrile as a solvent for phase seperation by emulsion and HPC[Hyroxypropyl cellulose] as dispersant, well dispersed spherical mullite powder was synthesized. From the result of TG-DTA analysis of dried gel, an exothermic peak was appeared at about 980℃ and it was thought that the procedure of crystallization would arise at over this temperature. Also from the results of XRD of calcined powder, the peak of Al-Si spinel was appeared at the sample which is calcined at 1000℃ fOr 10 hours and the peak of mullite was appeared at 1300, 1400℃ for 3 hours. The former sample had an average particle size of 0.316 ㎛ but the latter samples had 0.277 and 0,267 ㎛ respectively in the form of sphere. This significant reduction of particle size resulted from structural transition of Al-Si spinel to mullite phase.