MOF-based interfacial phase inhibiting structural damage of carbon fiber reinforced polymer composites derived from high-energy irradiation

Metal-organic frameworks (MOFs) were strategically integrated into the interfacial region of carbon fiber reinforced polymer (CFRP) composites to investigate their mitigation effects on γ-ray irradiation-induced microstructural degradation. Systematic irradiation experiments were conducted at doses of 0, 250, 500 and 1000 kGy under ambient conditions. Scanning electron microscopy (SEM) results demonstrate that significant debonding and cracking of interfaces exposed to air media at irradiation doses of 500–1000 kGy, concomitant with an increase in oxygen content in the interfacial region is revealed by Energy Dispersive Spectroscopy (EDS). Oxygen permeation along the cracked interfaces into the CFRP interior, driven by irradiation, leading to an increase in the modulus and thickness of the “internal interface” as characterised by nanoindentation tests. In contrast, the MOF-modified composites effectively mitigated interfacial cracking, reducing the expansion of the interfacial layer thickness due to oxygen diffusion from 50 % (pristine) to 33 % (MOF-modified). Nanoscale infrared spectroscopy (nano-IR) demonstrated the MOF modification reduced the radiation-induced carbonyl and amide groups in the near-interface region, confirming suppressed oxidative degradation. Finally, three-point bending tests validated the macroscopic relevance, showing that MOF modification reduced the flexural strength loss from 12.3 % (unmodified) to 7.5 % after 1000 kGy irradiation. This work provides microscopic scale insights into interfacial radiation damage mechanisms and establishes a MOF-based interfacial engineering strategy to simultaneously block oxidative pathways and neutralize radiation species, advancing the design of radiation-resistant CFRPs for extreme environments.