Structure of intercalated organic montmorillonite and its pyrolysis properties analyzed using the Agrawal integral equation

We prepared intercalated organic montmorillonite (OMMT) from a pristine MMT and long-alkyl-chain quaternary ammonium salts (LACQAS). X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analyses revealed that the amount, carbon atoms, and alkyl chains of LACQAS influenced the large value of d(001) of OMMT significantly. The d(001) stabilized at 100–150 mmol·(100 g)-1 of LACQAS/MMT. The single LACQAS cations arranged in the form of a lateral layer or half-paraffin-type molecular structure between MMT layers, whereas the dual and triple LACQAS cations arranged in the form of a paraffin-type molecular structure. The pyrolysis temperature and maximum pyrolysis rate of OMMT increased greatly compared with those of MMT. The thermal weight loss of MMT was caused by the removed absorbed and structural water, whereas that of OMMT was by the pyrolysis of LACQAS. With the help of the Agrawal integral equation, the pyrolysis kinetics of MMT and OMMT were obtained using a trial-and-error method.