Resistance of amorphous boron powder/silicone rubber composites to gamma radiation aging

Abstract

In cutting-edge fields such as nuclear medicine, aviation, and aerospace, polymer materials face severe challenges owing to long-term exposure to extreme radiation environments. These environments impose stringent requirements on the service reliability of materials, which makes it imperative to improve the radiation resistance and aging resistance of polymer materials. To this end, amorphous boron powder (B) was used to prepare amorphous boron powder/silicone rubber (B/SR) composites because of the possible radical-scavenging characteristics of the empty orbitals present on the outer layer of amorphous boron powder. The impact of B on the radiation resistance of silicone rubber was investigated through systematic studies on the changes in the mechanical, thermal, and crosslink density properties of the material before and after irradiation. The experimental findings demonstrated that, at an absorbed dose of 200 kGy, the retention rate of elongation at break of B/SR0.3 sample can be maintained at (49.4±3.1)%, whereas pure SR is only (24.7±2.7)%. The initial breakdown temperature of irradiated silicone rubber composites raised from 454.9 °C to 472.8 °C by adding 0.3 parts of B, which significantly enhanced its thermal stability in radiation environments. To visually demonstrate the changes in the internal radicals of the silicone rubber composite during irradiation, this study used a UV lamp-electron paramagnetic resonance (UV-EPR) spectrometer for real-time monitoring and revealed that B could effectively eliminate the free radicals generated in the silicone rubber composite during the irradiation process. This study provides an effective strategy to improve the radiation resistance of silicone rubber composites and lays a solid foundation for the development of novel radiation-resistant polymer materials.

Keywords

• silicone rubber
• radiation effects
• inorganic nanoparticles
• free radical scavenging