Thermal decomposition kinetics of benzofuran derived polymer/organosilicate nanocomposites

Abstract

Benzofuran derived polymer poly(2-(5-bromo benzofuran-2-yl)-2-oxoethyl methacrylate)/organically modified montmorillonite nanocomposites were prepared via in situ polymerization technique. Vinyl benzyl dimethyl hexadecyl ammonium chloride was used as organic-modifier. X-ray diffraction analysis showed the silicate dispersion in the polymer matrix with an exfoliated structure. The thermal stabilities of nanocomposites were increased with loading organosilicate in the polymer matrix. The decomposition temperature of 5 wt% organosilicate nanocomposite at 10% weight loss was approximately 14 degrees C higher than that of pure polymer. Kinetic analysis of the decomposition process in nanocomposites was evaluated from dynamic experiments by means of Flynn-Wall-Ozawa and Coats-Redfern methods within 12% - 22% decomposition conversion range. Introduction of the silicate phase in polymer enhanced the apparent activation energy from 163.31 kJ/mol to 195.28 kJ/mol. The mechanism of thermal degradation for pure polymer in this conversion range probably followed a deceleration type phase boundary controlled reaction (R-3), whereas in case of nanocomposites, it shifted to dimensional diffusion type (D-n).