Syntheses of Opened Hollow Clay Microspheres through a Spray-Drying Approach and Their Derivative Clay/Carbon Nanotubes Composites

Opened hollow microspheres of organoclays were prepared via spray drying the suspension of modified Na + −montmorillonite (Na + -MMT) with alkylsulfonate. The microstructure and thermal properties of these opened hollow spheres were characterized by means of wide-angle X-ray diffraction, field emission scanning electron microscopy, and thermogravimetric analysis. The results showed that the organoclays had larger interlayer spacing compared with pure Na + -MMT and higher thermal stability relative to the alkylsufonate. The reason for the formation of this novel structure was investigated. On the basis of the morphological investigation of the organoclays containing alkylsulfonate with different molecular length, the formation of the opened hollow microspheres was found to be related to the intercalation structure of the organoclays. The larger the interlayer distance of the organoclays was, the more the opened hollow microspheres were formed. Moreover, intercalating Co 2+ ion within MMT galleries of the opened hollow microspheres via ion exchange could be applied to in situ synthesize clay/carbon nanotubes (clay/CNTs) composite by chemical vapor deposition after reduction.