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Silika basierende Aerogel‐Materialien mittels schneller Mikrowellen‐Trocknung erzeugt
Author(s) -
Durães L.,
Matias T.,
Patrício R.,
Portugal A.
Publication year - 2013
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201300140
Subject(s) - aerogel , methyltrimethoxysilane , materials science , microwave , volume (thermodynamics) , adsorption , distilled water , composite material , chemical engineering , thermal insulation , microwave oven , chromatography , chemistry , organic chemistry , layer (electronics) , physics , engineering , coating , quantum mechanics
Aerogel‐like silica based materials were obtained by microwave drying of the gels synthesized with methyltrimethoxysilane (MTMS) precursor. The microwave drying is an alternative ambient pressure drying technique for these nanostructured materials that allows a fast fine drying stage and avoids the high temperature cycles of conventional evaporative drying. The gels were synthesized by a two‐step acid‐base catalyzed sol‐gel process following the procedures described in an earlier work. After 2 days of aging, they were placed in an oven at 60°C, during one day, and then washed with distilled water at 40°C. Finally, the gels were dried in a microwave oven, at 450 W, in three cycles of two minutes each with two minutes of interval. During drying, a reduction of the gel volume was observed, but the major part of this volume was recovered by spring‐back effect in 2 days, giving aerogel‐like materials with a density in the interval 60–80 kg/m 3 . The final materials are monolithic, flexible and have a thermal conductivity of ˜0.04 W/(m K), which make them suitable for insulation applications. Additionally, they exhibit high hydrophobicity (contact angle ˜150°) and surface area (414 m 2 /g), what can be beneficial for adsorption of some organic pollutants.