Abstract
The surface mineral modification of montmorillonite (Mt) layers was carried out by removing some of the exchangeable cations and anions (salts) using dimethylformamide as a chelating agent. The rest unremoved exchangeable cations were balanced by the permanent negative charges in the Mt layers. The modified Mt layers were characterized by X-ray fluorescence, high-resolution scanning electron microscopy (HR-SEM), dynamic light scattering (DLS), and high-resolution transmission electron microscopy. The completely exfoliated modified Mt layers were composed of polyethylcyanoacrylate (PECA) at different ratios 1, 3, 5, 7, 10, and 15% (wt/wt). The obtained composites were investigated by molar mass, FTIR, small-angle X-ray diffraction, wide-angle X-ray diffraction, HR-SEM, DLS, and TGA. The results showed that the exchangeable cations and anions (salts) were removed from the surfaces of Mt layers, and all the percentages of loaded Mt layers were completely exfoliated in the bulk of PECA. TEM morphology exhibited clearly separated modified Mt layers due to removing the salts. SEM morphology showed highly exfoliated modified Mt layers in PECA bulk. TGA and nanoindentation data were showed increases in both thermal stability and mechanical properties of prepared composites by increasing the ratios of modified Mt layers in the bulk of PECA.