Boron particles acting as antioxidants for fluorosilicone rubber due to their radical scavenging activity.

Abstract The heat resistance enhancement of fluorosilicone rubber (FSR) can make it more suitable for cutting-edge applications and extreme conditions. This paper focused on the antioxidant properties of boron particles for FSR and the corresponding mechanism. The thermal stability of FSR and FSR/boron composites was characterized by thermal gravimetric analysis (TGA), isothermal degradation and thermal-oxidative ageing. The results showed that boron significantly improved the thermal stability of FSR. In particular, the FSR/boron (100/10) composite retained 95% of its weight after isothermal degradation at 350 °C for 12 h, while the FSR lost 55% of its weight within the initial 1 h. The antioxidant mechanism of boron was further investigated by chemiluminescence (CL), electron paramagnetic resonance (EPR) and vulcanization curves. It was shown that boron has powerful radical scavenging activity (RSA) and inhibited the oxidation scission of the side groups. Moreover, boron revealed no RSA towards the tert-butoxy radical, ensuring the good vulcanization of the FSR/boron composites. Highlights • Boron particles revealed definite enhancement effect due to their strong interactions with the matrix polymer of FSR. • Boron particles could significantly improve the thermal stability of FSR by inhibiting the scission of side groups. • It has been proved boron has powerful radical scavenging activity. • The RSA of boron seems to be selective, and the FSR/boron could be well vulcanized using DBPH as vulcanizer. [ABSTRACT FROM AUTHOR]