Improvement the flame retardancy, thermal conductivity and mechanical properties of silicone rubber via silane coupling agent modified CNTs‐β‐FeOOH

Abstract Silicone rubber with its odorless and non‐toxic, high and low temperature resistance and other advantages is widely used in many fields, but its shortcomings of flammability and low thermal conductivity limit its application and development. Therefore, the research on flame retardant and thermal conductive silicone rubber is practically valueable. In this study, iron oxyhydroxide (β‐FeOOH) was synthesized on carbon nanotubes (CNTs) by in situ growth and added to silicone rubber after surface modification with γ‐aminopropyltriethoxysilane (KH550). The results showed that the limiting oxygen index (LOI) of methyl vinyl silicone rubber (VMQ) with the addition of one part of KH550@CNTs‐β‐FeOOH increased to 29.8%, its peak heat release rate (pHRR) and total heat release (THR) decreased by 40.1% and 30.2%, respectively, and its thermal conductivity increased to 0.3680 W/m·k. The flame‐retardant performance and thermal conductivity of the VMQ composite were significantly improved. The improvement of its flame retardancy was mainly due to the catalytic carbonization of CNTs and β‐FeOOH, which promoted the formation of dense carbon layers. The carbon layer insulates the exchange of oxygen and combustible gases. In addition, the thermal conductive network constructed by KH550@CNTs‐β‐FeOOH in the composite effectively improved the thermal conductivity of VMQ.