MOFs sacrificial evolution and polymer chains/MOFs interlocking: unraveling the radiation resistance mechanism of MOF-based interphase in CFRP via WAXS/SAXS/SANS

Radiation-induced degradation at the fiber-matrix interface significantly compromises the longevity of carbon fiber reinforced polymer (CFRP) composites in nuclear and space environments. In the study, a metal-organic framework (MOF)-modified interphase was constructed to mitigate interfacial failure in CFRP under a high γ-irradiation dose of 1500 kGy. To elucidate the underlying anti-radiation mechanisms, a MOF/epoxy nanocomposite system was employed as a surrogate model for MOF-based interphase of CFRP, allowing for precise characterization. Chemically, multi-spectral analysis demonstrate that MOFs eliminated radiation-induced oxygenated radicals and reduced surface oxide layer thickness by over 50%. Physically, Synchrotron Wide-Angle/Small-Angle X-ray Scattering reveal a “sacrificial” evolution mechanism of MOFs, wherein MOFs undergo lattice contraction and volume densification to dissipate radiation energy. Meanwhile, Small-Angle Neutron Scattering has for the first time confirmed that epoxy molecular chains intercalate into the surface micropores of MOFs, forming an interlocking network that maintains stable physical bonding even after the MOF crystals contract. Mechanically, driven by these synergistic mechanisms, the MOF-based interphase significantly enhances radiation resistance, suppressing the loss in interlaminar shear strength from 14.5% (unmodified) to 9.4% and flexural strength from 17.5% (unmodified) to 10.3%. This study provides critical insights into the multiscale radiation response of MOF-based interphases in CFRP, offering a promising strategy for developing highly radiation-resistant composites.