Synthesis, characterization and thermal stability of different polystyryl quaternary ammonium surfactants and their montmorillonite complexes

Three polystyryl quaternary ammonium salts have been synthesized from the reactions of trimethylamine with chloromethyl polystyrenes which were prepared by three different methods: free-radical co-polymerization, chloromethylation of polystyrene and anionic polymerization. Then the polystyryl-modified montmorillonites have been obtained from the ion exchange of sodium ions in the montmorillonites with polystyryl quaternary ammonium salts. The polystyryl quaternary ammonium salts have been characterized using proton nuclear magnetic resonance spectrometer (1H NMR), Fourier-transformed infrared spectrometer (FT-IR), and gel permeation chromatography (GPC). The thermal stability of the quaternary ammonium salts and their corresponding modified montmorillonites have been studied by thermo gravimetric analysis (TGA). TGA data have shown that the polystyryl ammonium salt and its modified montmorillonites obtained from the reactions of chloromethyl polystyrene which was prepared by anionic polymerization are the most stable ones respectively. X-ray diffraction (XRD) and transmission electronic microspectroscopy (TEM) analysis of these polystyryl-modified clays have shown that they are of intercalated structures or partial exfoliation with stacked clay layers.