Growth of CeCo-MOF in dendritic mesoporous organosilica as highly efficient antioxidant for enhanced thermal stability of silicone rubber

High-efficient rubber antioxidants for enhanced heat resistance without compromising mechanical properties remain an enormous and long-term challenge for the rubber industry. Herein, we employed the in-situ growth of Ce-doped Co-metal-organic framework (CeCo-MOF) in dendritic mesoporous organosilica nanoparticles (DMONs@CeCo-MOF, denoted as DCCM) to prepare a novel antioxidant that exhibit outstanding thermal stability. Dendritic mesoporous organosilica nanoparticles (DMONs) effectively alleviated the incompatibility of CeCo-MOF in the polymer matrix, and the effective scavenging of free radicals was attributed to the various oxidation states of metal ions in CeCo-MOF. Surprising, by adding only 0.5 phr (parts per hundred of rubber) of DMONs@CeCo-MOF to silicone rubber (SR), the retention rate of tensile strength increased from 37.3% to 61.6% after aging 72 h at 250 °C, and the retention rate of elongation at break of DCCM/SR1 composites reached 68%, which was 5.43 times of SR. The strategy of anchoring MOFs on the surface of silica also provides a viable method for preparing effective compound functionalized rubber antioxidant.