Silane‐functionalized Al2O3‐modified polyurethane powder coatings: Nonisothermal degradation kinetics and mechanistic insights

Abstract

AbstractThis 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.