Modification of anionic and cationic clays by zwitterionic imidazolium ionic liquid and their effect on the epoxy-based nanocomposites

Zwitterionic imidazolium-based ionic liquid (ZIL) constituted by imidazolium cation and sulfonate anion was used to modify both cationic and anionic clay minerals, represented by montmorillonite (Na+-Mt) and calcined hydrotalcite (CHT). The organophilized clays were characterized using X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The ZIL was successfully intercalated into the interlayer space of Na+-Mt, and incorporated at the surface of the CHT, as indicated by XRD and FTIR analysis. Then, the unmodified and modified clays were mixed with epoxy prepolymer based on diglycidyl ether of bisphenol A (DGEBA). The modified clays resulted in epoxy networked materials with higher intercalation degree, and good transparency, as indicated by XRD, transmission electron microscopy (TEM) and Ultraviolet- visible (Uv-Vis) spectroscopy. The best intercalation was observed for the systems containing modified montmorillonite (ZIL-Mt). In addition, the clay-epoxy nanocomposites were also characterized by dynamic-mechanical analysis (DMA).