Boron-Modified Phenolic Resin: Thermal Stability and Decomposition Mechanisms via Experiments and Simulations

In this study, a boron-modified phenolic resin system with enhanced thermal stability was developed through the incorporation of 4-hydroxyphenylboronic acid pinacol ester (4-HPBAPE). A multiple-scale methodology integrating experimental characterization with classical molecular dynamics (MD) and reactive force field molecular dynamics (ReaxFF MD) was employed to systematically investigate the T _g , thermal conductivity, and pyrolysis mechanisms of modified phenolic resins. Differential scanning calorimetry (DSC) measurements showed a 30 ℃ increase in T _g (159 → 189 ℃), while thermal conductivity testing revealed a 10% reduction (0.2154 → 0.1920 W/(m·K)). The errors between the results obtained from MD simulation and the experimental results were all less than 10%. Thermogravimetric analyzer (TGA) measurements indicated that the char yield decreased with increasing 4-HPBAPE doping ratio. ReaxFF MD simulations demonstrated that boron modification of phenolic resins enhanced the production of light hydrocarbons (C ₁ -C ₅ ) during pyrolysis, resulting in higher mass loss. This occured via boron-mediated ring-opening and suppression of large aromatic cluster formation. Future efforts could focus on controlling the bonding form of boron to suppress ring-opening reactions, thereby enhancing the char yield.