ABSTRACT: Polyurethane (PU) pyrolysis characteristics were investigated using reactive force field molecular dynamics simulations to reveal the product distribution and thermal decomposition mechanisms. A PU molecular model was constructed and simulated its pyrolysis process at 1,500-3,000 K, analyzing potential energy changes, product species, carbon-containing component distribution, main gas products, main intermediate products and initial cleavage pathways. At 1,500 K, PU mainly decomposes into NHCOO and CH2 fragments, with concurrent gas release. At 1,800-2,100 K, aromatic amines, olefins, and gases (including CO2, CO, and NH3) are formed through radical recombination. At higher temperatures (2,400-3,000 K), carbon rearrangement is promoted, yielding dense C
