Preparation of the monolith of hierarchical macro-/mesoporous calcium silicate ultrathin nanosheets with low thermal conductivity by means of ambient-pressure drying.
Chem Asian J
; 10(6): 1394-401, 2015 Jun.
Article
em En
| MEDLINE
| ID: mdl-25827818
ABSTRACT
Calcium silicate monolith was prepared by the hydrothermal reaction of a slurry of SiO2 , calcium hydroxide, and surfactant (OP-10) obtained by high-energy ball milling, followed by drying at ambient pressure. By using this strategy, the shrinkage due to the collapse of pores during the drying of porous materials, which is a commonly observed phenomena, was successfully avoided. It has a unique microstructure of hierarchical macro-/mesoporous ultrathin calcium silicate nanosheets with a layered gyrolite crystalline structure. Very interestingly, the calcium silicate nanosheets can be peeled off to give a single-layer nanosheet (1.23â
nm) of gyrolite by ultrasonication. The monolith has a low apparent density (0.073â
g cm(-3) ) and low thermal conductivity (0.0399â
W K(-1) m(-1) ). The reasons behind why the formation of the unique hierarchical macro-/mesoporous ultrathin nanosheets avoids shrinkage during the hydrothermal reaction and drying, and considerably decreases the thermal conductivity, is discussed.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article