Synthesis, characterization and thermal degradation kinetics of poly(3-acetylcoumarin-7-yl-methacrylate) and its organoclay nanocomposites
A new coumarin derived polymer poly(3-acetylcoumarin-7-yl-methacrylate), poly(ACMA), and its nanocomposites with different contents of organoclay were synthesized and characterized with FTIR and 1H-NMR. The X-ray diffraction analysis showed that the clay dispersion in the polymer matrix was exfoliated behavior. The influence of the organoclay content on the thermal stabilities of nanomaterials was studied by means of thermogravimetric analysis (TGA). Thermal stabilities of nanocomposites were increased about 29-38 °C by loading clay into the polymer matrix. The nanocomposite containing 4 wt% organoclay showed the best thermal stability (319 °C) at 10% weight loss. Thermal decomposition kinetic analysis of nanocomposites was investigated by Kissinger and Coats-Redfern methods. Introduction of the clay phase into homopolymer increased the activation energy from 185.39 kJ/mol to 264.30 kJ/mol. The actual reaction mechanism of pure poly(ACMA) and its organoclay nanocomposites obeyed deceleration type dimensional diffusion mechanisms (Dn).