Quaternized-poly(N-vinylimidazole)/montmorillonite nanocomposite: Synthesis, characterization and electrokinetic properties

In this study, it was aimed to bring together the superior properties of montmorillonite clay (MMT) and poly(N-vinylimidazole) (PVI). For this purpose, first PVI was synthesized by free radical polymerization and then quaternized (Q-PVI) to interact better with MMT. Afterwards, a new nanocomposite was prepared from Q-PVI and MMT by solution intercalation method. The obtained nanocomposite (Q-PVI/MMT) was characterized by several techniques such as FTIR, SEM, TGA, XRD and elemental analysis. Their conductivities and densities were also measured. Aqueous dispersions of MMT and Q-PVI/MMT were prepared and the effects of pH, temperature, various surfactants (anionic, cationic, and non-ionic) and electrolytes (mono-, di-, tri- valent, anionic, and cationic) on their ζ-potentials were determined by electrokinetic experiments. It was observed that Q-PVI/MMT had positive surface charge in the wide range of pH and showed isoelectric point (IEP), whereas MMT had negative surface charge in the whole range of pH with exhibiting no IEP. The electrostatic attractions between the Q-PVI and the surface of MMT were reduced upon the addition of NaCl resulting with reduced ζ-potential. Also, elevated temperatures caused slightly decrease in ζ-potential of Q-PVI/MMT.