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A polyurethane (PU)-based powder coating reinforced with vinyltrimethoxysilane (VTMS)-functionalized ZrO 2 nanoparticles (V-ZrO 2 ) for thermal stability was developed. Chemical structure, microstructure and thermal degradation kinetics of the prepared coatings were investigated. The peak of aliphatic C-H vibrating bond in the Fourier transform infrared (FTIR) spectrum of V-ZrO 2 was a signature of VTMS attachment. Scanning electron microscopy (SEM) images reveled that, by increase of V-ZrO 2 content from 0.1 to 0.3 wt.% and then 0.5 wt.%, some agglomerations of nanoparticles are formed in the PU matrix. Thermogravimetric analysis (TGA) of the PU/V-ZrO 2 powder coatings was performed at different heating rates nonisothermally to capture alteration of activation energy (E a ) of degradation of PU/V-ZrO 2 powder coatings as a function of partial mass loss by using Friedman, Kissinger-Akahira-Sunose (KAS), Ozawa-Wall-Flynn (FWO) and modified Coats-Redfern isoconversional approaches. It was observed that by addition of 1 wt.% V-ZrO 2 to PU resin the early state degradation temperature at 5% weight loss increased about 65 • C, suggesting a physical barrier effect limiting the volatility of free radicals and decomposition products. Incorporation of 5 wt.% ZrO 2 led to about 16% and 10% increase in E a and LnA of blank PU, respectively, which was indicative of higher thermal resistance of nanocomposite powder coatings against thermal degradation. There was also obvious agreement between model outputs and experimental data. The results reveal that nanocomposite coating shows superior thermal properties compared to neat PU powder coatings, and the presence of nano ZrO 2 in sufficient amount causes retardation of the thermal decomposition process.

This work reports on nonisothermal degradation kinetics of polyurethane (PU)‐based powder coatings containing 1, 3, and 5%wt% vinyltrimethoxysilane functionalized Al2O3 (V‐Al2O3) nanoparticles. Thermogravimetric analysis of PU/V‐Al2O3 powder coatings with different V‐Al2O3 contents has been performed at different heating rates. Variation of activation energy (Ea) of PU/V‐Al2O3 powder coatings was modeled as a function of partial mass loss by using Kissinger–Akahira–Sunose, Ozawa–Wall–Flynn and modified Coats–Redfern isoconversional approaches. The results revealed hindered decomposition process of PU/V‐Al2O3 nanocomposite powder coatings, featured by an increase in activation energy of degradation from ∼158 for blank PU to 225, 183, and 229 kJ/mol for nanocomposites filled with 1, 3, and 5 wt% of V‐Al2O3, respectively. Likewise, pre‐exponential factor values increased for samples containing V‐Al2O3 nanoparticles compared to that of blank sample. Sestak–Berggren kinetic model appropriately captured thermal degradation behavior of PU/V‐Al2O3 nanocomposites than that of nth order decomposition kinetic reaction models.