The thermal behaviour of microporous materials is relevant both for their characterization and for their application, and varies dramatically from one material to another. This paper intends to give a picture of their behaviour and to highlight analogies and differences in these materials as a function of their chemistry and topology. The information on their response to heating and dehydration/calcinations, even if still scanty and sometimes controversial, shows that some materials undergo dehydration-induced decrease in volume, which can be dramatic or very scarce as a function of the extraframework content. These changes in volume can be partially or completely irreversible if they involve structural modifications of the tetrahedral framework. It is to highlight that topological changes are always due to the so called "face sharing tetrahedral" process.
Phase transformations and structural modifications induced by heating in microporous materials
ALBERTI, Alberto;MARTUCCI, Annalisa
2005
Abstract
The thermal behaviour of microporous materials is relevant both for their characterization and for their application, and varies dramatically from one material to another. This paper intends to give a picture of their behaviour and to highlight analogies and differences in these materials as a function of their chemistry and topology. The information on their response to heating and dehydration/calcinations, even if still scanty and sometimes controversial, shows that some materials undergo dehydration-induced decrease in volume, which can be dramatic or very scarce as a function of the extraframework content. These changes in volume can be partially or completely irreversible if they involve structural modifications of the tetrahedral framework. It is to highlight that topological changes are always due to the so called "face sharing tetrahedral" process.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
