Atomistic simulation of the combustion of pyrolysis gases derived from silicone-modified phenolic nanocomposites

This study employs reactive molecular dynamics simulations to investigate the gas-phase combustion behavior of pyrolysis gases released from silicone-modified phenolic nanocomposites under high-temperature conditions relevant to atmospheric and Martian reentry. The effects of composite density, ambient oxygen content, and environmental gases (atomic O/N, O2, CO2) on combustion kinetics and reaction pathways are systematically analyzed. Results reveal that lower-density composites exhibit more intense gas-phase combustion, releasing greater heat and producing more low-molecular-weight hydrocarbons. Key reaction pathways for H2, CH4, H2O, and CO formation are identified, and activation energies for dominant mechanisms are quantified. Surface effects promote the emission of gaseous products, while volume ablation favors solid residue formation. These findings provide atomic-scale insights into pyrolysis gas combustion, supporting the development of high-fidelity ablation models for thermal protection systems.