Enhanced General Analytical Equation for the Kinetics of the Thermal Degradation of Poly(lactic Acid) / Montmotillonite Nanocomposites Driven by Random Scission

An enhanced general analytical equation has been developed in order to evaluate the kinetic parameters of the thermal degradation of nanocomposites, composed of poly(lactic acid) (PLA) and organo-modified montmorillonite (OMMT) nanoparticles. This improvement has consisted of replacing the n-order conversion function by a modified form of the Sestak-Berggren equation that led to a better adjustment of experimental data and also adequately represented the conventional mechanisms for solid-state processes. The kinetic parameters so obtained have been compared to those determined by conventional differential and isoconversional methods. Given that the thermal degradation of PLA has been argued to be caused by random chain scission reactions of ester groups, the conversion function , corresponding to a random scission mechanism, has been tested. Once optimized the kinetic model, the thermal degradation kinetics of nanocomposites (0.5 an was compared to that of the polymer * Corresponding author. Department of Chemical Engineering, Universitat de Girona, Campus Montilivi, s/n, 17071 Girona, Spain. Tel +34972418400, Fax: +34972418399, e-mail: [email protected] *Manuscript-revised (marked) Click here to view linked References