Synthesis of hydrophobic aerogels for transparent window insulation applications

Autor:	A. Venkateswara Rao, Gerard Pajonk, D. Haranath
Rok vydání:	2001
Předmět:	Materials science Methyltrimethoxysilane Mechanical Engineering Aerogel Condensed Matter Physics Catalysis Solvent chemistry.chemical_compound Volume (thermodynamics) chemistry Chemical engineering Mechanics of Materials General Materials Science Methanol Composite material Sol-gel Shrinkage
Zdroj:	Materials Science and Technology. 17:343-348
ISSN:	1743-2847 0267-0836
DOI:	10.1179/026708301773002572
Popis:	The present paper deals with the synthesis of hydrophobic aerogels using methyltrimethoxysilane (MTMS) as a hydrophobic agent for transparent window insulation applications. The molar ratio of methanol (solvent), water, and ammonia (catalyst) to the tetramethoxysilane (precursor) MeOH/H2O/NH4OH/TMOS was fixed at 12/4&/3·6×10-3/1 throughout the experiments and the MTMS/TMOS molar ratio M was varied from 0 to 1·55. After gelation, the alcogels were dried supercritically using the high temperature alcohol method. It has been found that lower ( 90% for a 10 mm thick sample at 800 mm wavelength) and negligible volume shrinkage ( 1·03) M values resulted in semitransparent ( 10% volume shrinkage but excellent hydrophobicity. A good compromise of acceptable optical transmittance (∼85% optical transmission at 800 ...
Databáze:	OpenAIRE
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