Screening of Phenolic Antioxidants for Synergistic Use With Antioxidant 4020 in Natural Rubber via Molecular Simulation

A multi‐scale molecular simulation approach integrating quantum mechanics (QM), molecular dynamics (MD), and Monte Carlo (MC) methods was developed for high‐throughput screening of phenolic antioxidants in natural rubber (NR). Fourteen candidates were systematically evaluated based on their OH bond dissociation energies, solubility parameters, transition states, compatibility, migration resistance, and oxygen barrier properties. Three antioxidants‐2246, 1076, and LK1081‐were identified as optimal candidates. Simulation results showed that their activation free energies for OH dissociation were significantly lower than that of the CH bond in NR (230.38 kJ/mol), indicating superior radical scavenging ability. LK1081 exhibited the lowest energy barrier, followed by 2246. The 2246/NR system showed the lowest solubility and permeability coefficients, implying excellent anti‐migration and oxygen barrier performance. Experimental validation confirmed that all three antioxidants effectively delayed thermo‐oxidative aging of NR. After 3 days, 2246/NR maintained the highest mechanical property retention (76.46% tensile strength, 68.61% elongation); after 5 days, 1076/NR performed best (30.5% tensile strength, 53.18% elongation). Thermogravimetric analysis revealed that LK1081/NR had the highest maximum decomposition temperature (383.94°C), followed by 2246/NR (382.63°C), both significantly higher than the conventional 4020/NR system (377.70°C). This work provides an efficient strategy for rational antioxidant selection in rubber compounding.