Preparation and Characterization of Organo Montmorillonite Modified by a Novel Gemini Surfactant

Abstract

A novel cetyl gemini surfactant (Gemini C16) was prepared and used as a modifier for sodium montmorillonite (Na-MMT). Two organo montmorillonites, i.e. Na-MMT modified by the novel gemini surfactant (Gemini C16-MMT) and Na-MMT modified by a conventional surfactant, cetyl trimethyl ammonium bromide (CTAB-MMT), were prepared by ion exchange of Na-MMT with two surfactants above respectively, with isopropanol as assisting intercalator. The modified MMTs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), derivative thermogravimetric analysis (DTG). X-ray diffraction (XRD), transmission electron microscopy (TEM), and dispersibility measurement. The FTIR spectra show that MMTs were not chemically bonded with the surfactants Gemini-C16 or CTAB after modifications, whereas there were physical bonds between them. Furthermore, the thermal analysis also proves this and indicates that the surfactants were just adsorbed on the sheet surface of MMTs. The XRD analysis shows that the interlayer space (d001) of Na-MMT increases due mainly to the long chain of quaternary ammonium salt. The d-spacing of Na-MMT modified by Gemini C16 increased from 1.60 nm to 4.90 nm, which was 2.2 times than that of Na-MMT modified by CTAB. The TEM phototgraphs show that the layers were partly separated when MMT was modified by Gemini C16. The dispersibility measurements suggests that the hydrophobicity of the modified Na-MMT was improved and Gemini C16-MMT was more hydrophobic than CTAB-MMT. The modified MMTs with greater gallery height would be expected to be useful for the preparation of polymer nanocomposite with better properties.