X-ray irradiation-induced real-time conductivity evolution and cumulative damage effects of epoxy-based shape memory polymers

Shape memory polymers (SMPs) for space deployable structures, as a new type of smart material, whose adaptivity to space environments plays a crucial role in ensuring the long-term stable operation of next-generation spacecraft. This study systematically investigates the real-time photoconductive response and cumulative damage effects of SMPs with varying crosslinking network architectures under X-ray irradiation. By tailoring the curing agent functionality and mass ratios, a series of SMPs are synthesized and evaluated through shape memory behavior, thermodynamic and dielectric properties, and conductivity characteristics with and without X-ray irradiation. The research emphasizes the effects of X-ray irradiation on their dielectric properties, not only examining damage effects but also closely monitoring the real-time evolution of charge transport properties during irradiation, with the influence of temperature on these properties simultaneously considered. The results demonstrate that X-ray exposure induces a sharp increase in conductivity, with an effect significantly greater than that of temperature, accompanied by a phenomenon resembling current saturation. And at high doses accumulation, leads to partial chain scission and the formation of new functional groups, indicating a simultaneous process of degradation and re-crosslinking. This work provides a foundational understanding of radiation effects on epoxy SMPs and practical guidance for their use in high-radiation environments.