Improving the Performance Stability of Phenolic‐Based Coatings Under High‐Dose Gamma‐Ray Irradiation via a Synergistic Strategy Combining Benzene Ring Barrier Structure and Cross‐Linking

To address the need for protective coatings that can withstand high‐dose gamma‐ray irradiation in nuclear facilities, this research proposes a synergistic strategy combining benzene ring barrier structures and cross‐linking design to enhance the radiation resistance of phenolic‐based coatings. Epoxy‐phenolic resin (EPN) was used as the matrix, and phenolic amine (PAA) was designed as the curing agent. The coating was subjected to gamma‐ray irradiation at cumulative doses ranging from 0 to 10,000 kGy. The structural evolution, surface morphology, thermal stability, tribological behavior, adhesion, gloss, color difference, and nuclear decontamination efficiency of the coating after high‐dose irradiation were systematically investigated. Results show that low‐dose irradiation (≤ 10 kGy) promotes further cross‐linking of unreacted epoxy groups, improving coating density, adhesion, and thermal stability. In contrast, high‐dose irradiation (≥ 1000 kGy) induces molecular chain scission and oxidation, leading to surface microcracks, yellowing, increased friction coefficient, and reduced adhesion. The coating might exhibit a dual‐stage response to irradiation, including benzene rings that passively dissipate radiation energy through π‐electron delocalization, while amine groups actively capture radicals and induce secondary cross‐linking. The work offers a viable molecular design strategy for protective coatings in extreme radiation environments.