Decomposition Kinetics and Thermal Stabilization via Interfacial Restrictions in PS/TiO2 Nanocomposites

This study investigates the structural morphology, chemical integrity, and non-isothermal decomposition kinetics of polystyrene (PS) nanocomposites incorporated with titanium dioxide (TiO2) nanoparticles (3, 5, and 10 wt %). Scanning electron microscopy (SEM) confirmed high nanoscale dispersion of quasi‑spherical clusters ranging between 32 and 69 nm within the polymer domain. Fourier transform infrared (FTIR) spectroscopy verified the structural integrity of the PS backbone alongside a progressive development of the characteristic Ti–O–Ti bridging framework below 800 cm–1. Solid-state kinetic analysis via a modified Coats–Redfern method revealed a non-linear dependency of the effective activation energy (Ea) on the conversion degree (α). Thermodynamic state functions (ΔG, ΔH, ΔS) demonstrate that the rigid TiO2 surfaces impose severe local spatial and entropic restrictions on the decomposing macromolecular radicals. This tortuous network successfully regulates the energetic landscape, offering a highly efficient mechanism for physical thermal stabilization.