Thermal Stability and Degradation Kinetic Studies of PVA/RGO Using the Model-fitting and Isoconversional (model-free) Methods

In this study RGO was prepared using Hummers method PVA/RGO nanofibers were produced by electrospinning method. The properties of the products were investigated using X-ray powder diffraction (XRD), Raman Spectroscopy and scanning electron microscopy (SEM). SEM measurements showed that the addition of RGO to the solution of PVA decrease the diameter of fibers. The effects of RGO on the electrical conductivity of PVA are investigated by electrochemical impedance spectroscopy (EIS). The nonisothermal kinetics of thermal degradation of PVA/RGO has been studied using thermogravimetric analysis (TGA). The activation energy (Ea) was calculated using model-fitting and isoconversional methods. Master-plot and model fitting methods were used to determine the appropriate conversion model f(α). It was established that the Friedman and Vyazovkin methods are the best two methods for describing the dependence of Ea on the degree of conversion (α) for this system.