Modeling the Initial Stage of Crosslinked Aromatic Hydrocarbon Polymer Pyrolysis

Ablative materials are employed as thermal insulators in hypersonic space vehicles and for fire proofing in commercial applications. However, the chemical reactions involved in the transformation of ablative materials to char during pyrolysis are not well understood. Reactive molecular dynamics simulations were performed to study the initial stage of the pyrolysis of crosslinked aromatic hydrocarbon polymers. The products formed were characterized and acetylene was found to be the primary product. The value of the activation energy for acetylene formation was estimated. The acetylene formation mechanisms were analyzed at different degrees of crosslinking and the graphitic precursor formation mechanism was studied.