کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
611979 880689 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Optimization of instantaneous solvent exchange/surface modification process for ambient synthesis of monolithic silica aerogels
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Optimization of instantaneous solvent exchange/surface modification process for ambient synthesis of monolithic silica aerogels
چکیده انگلیسی

The instantaneous solvent exchange/surface modification (ISE/SM) process for the ambient synthesis of crack-free silica aerogel monoliths with a high production yield was optimized. Monolithic forms of silica wet gels were obtained from aqueous colloidal silica sols prepared via the ion exchange of sodium silicate solutions. Crack-free silica aerogel monoliths were synthesized via an ISE/SM process using isopropyl alcohol/trimethylchlorosilane as a modification agent and n-hexane as a main solvent, followed by ambient drying. The optimum process conditions of the ISE/SM process were investigated by clarifying the reaction mechanism and phenomena. Most effective ranges of process variables on the ISE/SM stage were determined as 0.2500–0.3567 of TMCS/H2O (pore water) in molar ratio and 15–30 of n-hexane/TMCS in volumetric ratio, with a reaction temperature below 283 K. Crack-free silica aerogel monoliths synthesized via these conditions had a well-developed mesoporous structure and excellent properties (bulk density of 0.12–0.14 g/cm3, specific surface area of 724 m2/g), and a high yield (nearly 80%).

The effective synthetic conditions for crack-free silica aerogel monoliths via the ISE/SM process and ambient drying were successfully optimized.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 322, Issue 1, 1 June 2008, Pages 224–230
نویسندگان
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