Thermal Characterization of Surfactant-modified Montmorillonites
Frost, Ray L., He, Hongping, Ding, Zhe, Xi, Yunfei, Zhu, Jianxi, Yuan, Pen, & Yang, Dan (2005) Thermal Characterization of Surfactant-modified Montmorillonites. Clays and Clay Minerals, 53(3), pp. 287-293.
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The thermal stability of surfactant-modified clay plays a key role in the synthesis and processing of organoclay based nanocomposites. Differential thermal analysis (DTA), thermogravimetric measurement (TG) and differential scanning calorimetry (DSC) were used in this study to characterize the thermal stability of hexadecyltrimethylammonium bromide (HDTMAB) modified montmorillonites prepared at different surfactant concentrations. DSC shows that the molecular environment of the surfactant within the montmorillonite galleries is unique from that in the bulk state. The endothermic peak at 70-100 oC in the DTA curves of the modified montmorillonites is attributed to both the surfactant phase transformation and the loss of free and interlayer water. With an increase of surfactant packing density, the amount of water residing in the modified montmorillonite decreases gradually, reflecting the improvement of the hydrophobic property for organoclay. However, the increase of the surfactant packing density within the galleries leads to the decrease of the thermal stability of the organoclays.
With an increase of initial surfactant concentration for the preparation of organoclays, the surfactant packing density increases gradually to a "saturated" state. It was found that the cationic surfactant was introduced into the montmorillonite interlayer not only by cation exchange but also by physical adsorption.
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|Item Type:||Journal Article|
|Additional Information:||Self-archiving of the author-version is not yet supported by this publisher. For more information, please refer to the journal’s website (see link) or contact the author. Author contact details: email@example.com|
|Keywords:||Surfactant, modified montmorillonite, DTA, TG, DSC, thermal stability|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Science and Technology|
|Copyright Owner:||Copyright 2005 Clay Minerals Society|
|Deposited On:||06 Apr 2006|
|Last Modified:||29 Feb 2012 23:14|
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