New Insights into Phenolic Resin Decomposition under Oxidative Conditions of High Temperature

Phenol-formaldehyde (PF) resin, a significant synthetic thermosetting polymer, is extensively utilized across diverse engineering domains. The exploration of the high-temperature oxidation mechanism of PF resin is pivotal to enhancing its thermal stability. However, current research lacks a comprehensive study on the pyrolysis mechanism of PF resin under different oxidizing conditions. Herein, this work systematically explores the pyrolysis mechanism of PF resin under various high-temperature oxidation environments by using pyrolysis experiments and molecular dynamics simulations. The high-temperature oxidative cracking experiment revealed that the major liquid products from phenolic resin are single-ring aromatic compounds, such as phenol, benzene, and cresol. As the temperature increases, the proportion of phenol increases while that of m-cresol decreases. The Kissinger method determined the activation energies and mechanisms of the four-step oxidation reactions. ReaxFF simulations validate that the erosion products and mechanisms of oxygen on PF are consistent with the experiment and further explore the bombardment effects of different high-energy oxygen. It was found that oxygen caused greater damage to the resin than atomic oxygen by breaking bonds, such as C–H and C═C, producing a richer array of products. This study elucidates the reaction mechanisms of gaseous byproducts, including H2, OH, C2H2, and CO2, which are released during the oxygen bombardment process on phenolic resin. These findings offer new insight into the high-temperature pyrolysis of resin under extreme oxidative conditions and enrich our understanding of the complex interactions between material properties and environmental factors.