Surface modification and reinforcement of silica aerogels using polyhedral oligomeric silsesquioxanes.
Langmuir
; 28(43): 15362-71, 2012 Oct 30.
Article
em En
| MEDLINE
| ID: mdl-23046155
ABSTRACT
This study evaluated polyhedral oligomeric silsesquioxane (POSS) molecules as useful, multifunctional reinforcing agents of silica aerogels. Silica aerogels have low-density and high surface area, although their durability is often compromised by the inherent fragility and strong moisture absorption behavior of the silica networks. POSS molecules carrying phenyl, iso-butyl, and cyclohexyl organic side groups, and several Si-OH functionalities were incorporated into silica networks via reactions between Si-OH functionalities in POSS molecules and silanes. Solid state (13)C and (29)Si NMR spectra established that greater than 90% of POSS molecules grafted onto silica networks and led to an increase in fractal dimensions. An almost 6-fold increase in compressive modulus was achieved with less than 5 wt % trisilanol phenyl POSS, and a 50-fold decrease in polarity with negligible changes in density were seen in aerogels modified with less than 5 wt % trisilanol isobutyl POSS.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Langmuir
Assunto da revista:
QUIMICA
Ano de publicação:
2012
Tipo de documento:
Article