Ion Exchanged Vermiculites with Lower Expansion Onset Temperatures

South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. In the exchanged vermiculite with ammonium ions, it was found that ammonia and water were the blowing agents and they were simultaneously released during thermal deg...

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Bibliographic Details
Published in:Molecular Crystals and Liquid Crystals 2012-04, Vol.555 (1), p.65-75
Main Authors: Muiambo, HermÍNIO F., Focke, Walter W.
Format: Article
Language:English
Subjects:
Ammonia
Blowing agents
Crystals
Exchanging
exfoliation
Heat transfer
interstratification
Ion exchange
Ion exchangers
Liquid crystals
Minerals
Sodium
Temperature effects
thermal analysis
Thermal degradation
Vermiculite
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Summary:South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. In the exchanged vermiculite with ammonium ions, it was found that ammonia and water were the blowing agents and they were simultaneously released during thermal degradation. In the increasing ionic potential series: Na, Ba, Ca and Mg, it was found that the onset expansion temperature also increased dramatically. Exchange with relatively low ionic potential species, namely sodium, potassium and ammonium, lowered the exfoliation onset temperature of vermiculite to below 300°C.
ISSN:1542-1406
1563-5287
1527-1943
DOI:10.1080/15421406.2012.634367