Silane‐functionalized Al 2 O 3 ‐modified polyurethane powder coatings: Nonisothermal degradation kinetics and mechanistic insights

This work reports on nonisothermal degradation kinetics of polyurethane (PU)‐based powder coatings containing 1, 3, and 5%wt% vinyltrimethoxysilane functionalized Al 2 O 3 (V‐Al 2 O 3 ) nanoparticles. Thermogravimetric analysis of PU/V‐Al 2 O 3 powder coatings with different V‐Al 2 O 3 contents has been performed at different heating rates. Variation of activation energy ( E a ) of PU/V‐Al 2 O 3 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‐Al 2 O 3 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‐Al 2 O 3 , respectively. Likewise, pre‐exponential factor values increased for samples containing V‐Al 2 O 3 nanoparticles compared to that of blank sample. Sestak–Berggren kinetic model appropriately captured thermal degradation behavior of PU/V‐Al 2 O 3 nanocomposites than that of n th order decomposition kinetic reaction models.