Effect of intercalation agents on morphology of exfoliated kaolinite

Abstract

Kaolinite intercalation compounds were prepared by intercalating fatty acids and quaternary ammonium salts into kaolinite layers, using methanol-grafted kaolinite as the precursor. Meanwhile, massive lamellas were exfoliated during the intercalation process. The interlayer structure, chemical bonding and morphology of kaolinite before and after intercalation were characterized in detail. As the alkyl chain length increases, the basal spacing of kaolinite increases gradually. The morphology analysis indicated that the ionic type of intercalation agent has a more important influence on the morphology change of kaolinite than their alkyl chain length. The initial kaolinite layers were mostly transformed into nanoscrolls in the product intercalated with stearyl trimethyl ammonium chloride (STAC). The present study demonstrates the arrangement model of intercalated molecules between kaolinite layers using X-ray diffraction (XRD) in conjunction with Fourier transform infrared (FTIR) and stereochemical calculation. On the basis of a probed arrangement model, the mechanism of effect of the alkyl chain length and ionic type of intercalation agent on the morphology of exfoliated kaolinite is suggested.