High-performance antioxidant behavior of zeolitic imidazolate framework-67 at low filler content in silicone rubber

The trade-off between increased heat resistance and deterioration of mechanical properties caused by excess heat-resistant additives limits the use of silicone rubber (SR) in cutting-edge applications and extreme conditions. In this study, a novel SR composite with ultrahigh thermal oxygen stability was developed by blending SR with a small amount of cobalt-based metal-organic framework (zeolitic imidazolate framework-67, ZIF-67). The addition of only 0.125–0.5 wt% (relative to the content of SR) of ZIF-67 to SR could effectively improve its thermal-oxidative stability. Specifically, after 12 days of aging, the retentions of elongation at break of ZIF-67/SR composite reached 28.3–60.7% of the original, while the maximum decomposition temperature of ZIF-67/SR was approximately 25–30 ℃ higher than that of pristine SR. The origin of these attractive characteristics of the ZIF-67/SR composites was investigated by carrying out electron spin resonance (ESR) and X-ray absorption fine structure (XAFS) analyses.