Aggregative Structure of the 1-Octadecyl-3-methylimidazolium Cation in the Interlayer of Montmorillonite and Its Effect on Polypropylene Melt Intercalation

Abstract

A series of organomontmorillonites were synthesized from pristine sodium montmorillonite via ion exchange in toluene with 1-octadecyl-3- methylimidazoliuni chloride, a kind of ionic liquid with high thermal stability, as a modifier. The amount and aggregative state of the 1-octadecyl-3- methylimidazolium cation ([C18mim]+) adsorbed in the interlayer of organomontmorillonite (MMT) were investigated with thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and differential scanning calorimetry. XRD patterns showed that [C18mim]+ was successfully intercalated into the interlayer of MMT, and the interlayer distances of the clays increased dramatically. On the basis of the TGA results, three types of arrangement models of [C18mim]+ could be seen, and they were related to the loading level of [C18mim]+ in the gallery of MMT. The effects of the aggregative structure of [C18mim]+ in the interlayer of MMT on polypropylene melt intercalation was also examined. © 2007.