솔-젤법에 의한 다공성 실리카 세라믹스의 제조-$H_2O/TEOS$ 몰비의 영향-

Porous silica ceramics prepared by sol-gel process-Effect of $H_2O/TEOS$ molar ratio-

  • 이진휘 (서울산업대학교 화학공학과) ;
  • 김화중 (건국대학교 공업화학과) ;
  • 이준 (건국대학교 공업화학과)
  • Lee, Jin-Hui (Dept. of Chemical Eng., Seoul National Polytechnic Univ) ;
  • Kim, Wha-Jung (Dept. of Industrial Chemistrt, College of Eng., Kon-Kuk Univ) ;
  • Lee, Joon (Dept. of Industrial Chemistrt, College of Eng., Kon-Kuk Univ)
  • 발행 : 1997.02.01

초록

TEOS와 에탄올의 양을 고정하고 H2O/TEOS의 몰비가 2.6-59.0이 되는 범위에서 염산촉매를 사용하여 다공성 실리카 세라믹을 제조하였다. 서로 다른 조성의 솔 9종을 만든 후 젤화시간 측정, TG/DTA에 의한 건조시료의 열분석 및 FT-IR과 X-ray diffractometer에 의한 중간생성물의 특성분석을 수행하였고 50$0^{\circ}C$까지 열처리한 시료의 FT-IR에 의한 SiO2폴리머 분석, N2-adsorption isotherm을 이용한 비표면적과 기공크기분포 조사 및 TEM에 의한 SiO2폴리머의 형태와 기공의 변화를 조사하였다. 적용된 조성 및 촉매의 농도에서 최소 젤화반응시간은 TEOS1몰달 물의 양이 약 11몰에서, 가장 높은 중합도는 약 8-18몰에서, 그리고 가장 큰 비표면적값은 약 11몰에서 보였다. 이것은 물의 양이 약 11몰일 때 중합반응이 가장 빠르게 진행하였음을 의미한다. 결론적으로, 물의 양이 증가함에 따라서 약 11몰까지는 반응이 빠르게 진행되나 그 이상의 물이 사용될 경우 과잉의 물이 반응저해요인으로 작용하여 젤화시간의 지연 및 비표면적의 감소를 보인다.

Porous silica ceramics were prepared(with HCI catalyst) using H2O/TEOS molar ratios of 2.6~59.0, with the EtOH/TEOS ratio fixed. After preparing 9 kinds of sol, the followings were investigated; measurement of the gelation time, thermal analyses by TG/DTA, property analyses of the intermediates by FT-IR and X-ray diffractometry with dried samples, analyses of SiO2 polymer by FT-IR, the investigation of specific sur-face area and pore size distribution by N2-adsorption isotherm, and structural change of SiO2 polymer and pore morphology by TEM observation, with samples heat-treated to 50$0^{\circ}C$. In the concentrations of in-vestigated compositions and catalyst, gelation time showed a minimum at ca. 11 moles of water per one mole of TEOS, the highest degree of polymerization at ca. 8-18 moles, and the largest specific surface area at ca. 11 moles, which means that the polymerization proceeded fastest at ca. 11 moles of water. In con-clusion, the more water used, the faster the polymerization reaction up to ca. 11 moles, but more than ca. 11 moles of water caused retardation of gelation and resultant reduction of specific surface area.

키워드

참고문헌

  1. J Memb. Sci. v.10 no.81 The growth of membrane technology H. K Lonsdale
  2. J. Mater Sci. v.19 The preparation and characterization of alumina membranes with ultra-fine pores A. F. M. Leenaars;K Keizei;A. J Burggraaf
  3. J. Memb. Sci. v.39 no.213 Pore structures of sol-gel silica membranes L C. Klein;D. Gallagher
  4. J. Memb. Sci. v.92 no.29 Characterization of ceramic membranes,ⅠThermal and hydrothermal stabilities of commercial 40Å membranes G. R. Gallaher;P. K. T. Liu
  5. J. Memb. Sci. v.92 no.45 Characterization of ceramic membranes, Ⅱ Modified commercial membranes with pore size under 40Å C. L. Lin;D L. Flowers;P. K. T. Liu
  6. J. Memb. Sci. v.39 Titania and alumina ceramic membranes M. A. Anderson;M. J Gieselmann;Qunyin Xu
  7. J. Memb. Sci. v.39 no.221 Microporous alumina membranes H. P. Hsieh;R. R. Bhave;H. L. Fleming
  8. J. Memb. Sci. v.44 Silica membranes by the sol-gel process A. Larbot;A. Julbe;C. Guizard;L. Cot
  9. J. Memb. Sci. v.39 Inorganic membranes obtained by sol-gel techniques A. Larbot;J P. Fabre;C. Guizard;L. Cot
  10. J. Memb. Sci. v.99 no.57 Formation and characterization of supported microporous ceramic membranes prepared by sol-gel modification techniques R. S. A. de Lange;J. H. A. Hekkink;K. Keizer;A. J. Burggraaf
  11. J. Memb. Sci. v.79 no.65 Experimental studies on pore size change of porous ceramic membranes after modification Y. S Lin;A. J. Burggraaf
  12. J. Amer. Chem. Soc. v.50 no.3058 Alkyl orthosilicate A. W. Dearing;E. E. Reid
  13. J. Non-Cryst. Solids v.63 no.261 Generation of SiO₂-membranes from alkoxysilanes on porous supports A. Kaiser;H. Schmidt
  14. J. Non-Cryst. Solids v.48 no.31 The sol-gel transition in the hydrolysis of metal alkoxides in relation to the formation of glass fibers and films S. Sakka;K. Kamiya
  15. J. Col. Interface Sci. v.109 no.1 Silica membranes by the sol-gel process D. Gallagher;L. C. Klein
  16. J. Non-Cryst. Solids v.72 The effect of the H₂O/TEOS ratio on the structure of gels derived by the acid catalysed hydrolysis of tetraethoxysilane I. Strawbridge;A. F. Craievich;P. F. James
  17. J. Polym. Sci,· Part A: Polymer Chemistry v.24 Hydrolytic polycondensation of alkoxysilanes and modification of polymerization reactions B. E. Yoldas
  18. J. Non-Cryst. Solids v.130 no.8 Structures and properties of silica gels prepared by the sol-gel Method Jae Chul Ro;In Jae Chung
  19. J. Non-Cryst. Solids v.48 no.47 Sol-gel transition in simple silicates C. J. Brinker;K. D. Keefer;D. W. Shacfer;C. S. Ashley
  20. J. Non-Cryst. Solids v.63 no.50 Sol-gel transition in simple silicates Ⅱ C. J. Brinker;K. D. Keefer;D. W. Shaefer;R. A. Assink;B. D. Kay;C. S. Ashley
  21. J. Non-Cryst. Solids v.147;148 Structure tailoring of alkoxide silica J. Y. Ying;J. B. Benziger
  22. Sol-Gel Science Filters and membranes by the sol-gel process C. J. Brinker;G. W. Scherer
  23. J. Non-Cryst. Solids v.37 no.191 Glass formation through hydrolysis of Si(OC₂$H_5$)₄ with NH₄OH and HCl solution N. Nogami;Y. Moriya
  24. Sol-Gel technology for Thin Films, Fibers, Preforms, Electronics and Specialty shapes Filters and membranes by the sol-gel Process L. C. Klein
  25. J. Mater. Sci. v.14 no.607 Low temperature synthesis of a monolithic silica glass by the pyrolysis of a silica gel M. Yamane;S. Aso;S. Okano;T. Sakaino
  26. J Non-Cryst. Solids v.180 no.193 Infrared study of SiO₂ sol to evolution and gel aging D. Niznansky;J. L. Rehspringer
  27. The infrared spectra of minerals, H. H. W. Moenke;V. C. Farmer
  28. J. Non-Cryst. Solids v.107 no.199 Heat evolution, light scattering, and infrared spectroscopy in the formation of silica gels from alkoxides D. L. Wood;E. M. Rabinovoch
  29. J. Phys. Chem. v.63 no.179 An infrared study of the water-silica gel system H. A. Benesi;A. C. Jones
  30. J. Phys. Chem. v.62 no.1168 Surface functionality of amorphous silica by infrared spectroscopy R. S. McDonald