Thermal analysis of conducting polymers. Part 3. Isothermal thermogravimetry of doped and pristine polyaniline

Abstract

A study of the thermooxidative decomposition of electroactive polyanilines (PANI) has been carried out using isothermal thermogravimetry (TG). At low decomposition temperatures the process is governed by first-order kinetics, while at higher temperatures the decomposition is controlled by a one-dimensional diffusion mechanism. This has been attributed to changes in sample geometry, viscosity, and secondary cross-linking reactions and structural rearrangement at high temperatures which make it more difficult for the volatile fragments to diffuse to the surface of the polymer matrix. The activation energy ΔE values for the expulsion of free water/HCl and dopant HCl have been determined from the Arrhenius plots and are in good agreement with those obtained previously by differential scanning calorimetry (DSC). © 1993.