Enhancing radiation resistance of silicone rubber through the addition of polydopamine-modified cerium dioxide

With the widespread use of nuclear science and technology, slowing down the aging of polymers in a radiation environment has become a matter of great concern. In this work, cerium dioxide (CeO2) and CeO2 encapsulated with dopamine (PDA@CeO2) were selected as special fillers to prepare the silicone rubber (SR) composites, and their radiation resistance were investigated by comparing the mechanical properties and thermal performance before and after irradiation. The interfacial bridge formed by PDA results in a greater elongation at break for PDA@CeO2/SR5.0 (770.0 ± 33.6 %) than for CeO2/SR (686.0 ± 15.0 %). After irradiation with γ-rays, the retention of elongation at break of both CeO2/SR0.1 and PDA@CeO2/SR0.1 were larger than SR. Furthermore, PDA@CeO2/SR0.1 showed an impressive retention of 90.5 ± 2.7 % of the tensile strength retention after exposure to an absorbed dose of 200 kGy. The disparity in crosslink density prior to and following irradiation indicated that both CeO2 and PDA@CeO2 were efficacious in reducing radiation crosslinking within the SR. An electron paramagnetic resonance spectrometer and an ultraviolet lamp (UV-EPR) were used to observe in real time the free radical scavenging ability of CeO2 and PDA@CeO2 inside the SR. These results indicated that CeO2 and PDA@CeO2 was expected to prevent further chain reactions in silicone rubber by scavenging free radicals generated in SR, thus improving the radiation resistance of SR.