Enhanced thermal stability and structural behavior of terbium-doped polyaniline-multiwalled carbon nanocomposite

Terbium chloride doped polyaniline/multiwalled carbon nanotube (Tb-PAniMW) nanocomposite was effectively prepared via an oxidative polymerization method to examine the effect of rare-earth metal doping on the structural and thermal characteristics of conductive polymer nanocomposite. The incorporation of Tb³⁺ ions within the PAni/MWCNT framework was established through FT-IR spectroscopy, which exhibited the major characteristic absorption bands at 1585 cm⁻¹ and 1485 cm⁻¹ related to the quinonoid (Q) and benzenoid (B) units of polyaniline. The Morphological studies of Scanning Electron Microscopy (SEM) revealed a compact nanostructured surface with homogeneous distribution of the dopant throughout the nanocomposite matrix. Thermogravimetric analysis confirmed a three-stage degradation process, with overall weight losses observed of 40.07% to 46.80% at heating rates between 10 and 50 °C min⁻¹. The maximum residue of 59.93% obtained at 30 °C min⁻¹ indicates enhanced resistance to thermal decomposition. The Kinetic estimation showed activation energy values in the range of 12.33–55.10 kJ mol⁻¹, which reflecting the variations in the decomposition mechanism across different degradation stages. The positive enthalpy values proposed an energy fascinating degradation process, whereas negative entropy values specified the formation of a more organized activated state during decomposition. The Gibbs free energy values observed between 81.26 and 213.08 kJ mol⁻¹ confirmed the thermodynamic stability of the polymer matrix. The improved thermal resistance achieved through terbium chloride incorporation of PAni/MWCNT nanocomposites for advanced functional and energy-related applications.