Gelation behavior and phase separation of macroporous methylsilsesquioxane monoliths prepared by in situ two-step processing
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An in situ two-step processing using an initial acid catalysis step accompanied by an epoxide-mediated condensation step in the presence of ammonium chloride (NH4Cl) is reported, and macroporous cocontinuous methylsilsesquioxane (MSQ) monoliths have been successfully prepared by this processing. We explain the hydrolysis, gelation behavior and phase separation of MTMS(methyltrimethoxysilane)-MeOH(methanol)-HCl-PO(propylene oxide) system and the in situ effect of NH4Cl, and examine the macroporous morphology and pore structures of MSQ monoliths obtained under different conditions. Macroporous MSQ monolith under optimized conditions possesses a narrow macropore size distribution between 3 to 10 μm, surface area as high as 366 m2·g−1 and minimal shrinkage of only 1 %.
KeywordsMethylsilsesquioxane Monolith Sol–gel process Phase separation Ammonium chloride
- 13.Yin G, Yuan Q, Ning Z (2012) J Electroceram 28:70Google Scholar