Polymerizable ionic liquids for the preparation of polystyrene/clay composites

Abstract

Polymerizable ionic liquids (ILs) 1-methyl-3-(4-vinylbenzyl)imidazolium chloride, 1-hexyl-3-(4-vinylbenzyl)imidazolium chloride and 1-dodecyl-3-(4-vinylbenzyl)imidazolium chloride were prepared and used as new surfactants for the modification of montmorillonite (MMT). Functionalized MMTs were prepared by cationic exchange between sodium MMT and each of the ILs. Polystyrene (PS)/MMT composites were subsequently prepared by in situ intercalative free radical polymerization of styrene containing dispersed organophilic MMT. Exfoliation of MMT in the PS matrix was achieved only for MMT functionalized with the 1-dodecyl-3-(4-vinylbenzyl)imidazolium-based IL as revealed by X-ray diffraction and electron microscopy. The exfoliated composites showed good transparency and higher decomposition temperature than virgin polymer matrix, particularly pronounced under air atmosphere (Tmax = 66 degrees C), data comparable to or even greater than those reported in the literature for exfoliated PS nanocomposites