Facile preparation and flame retardancy mechanism of cyclophosphazene derivatives for highly <scp>flame‐retardant</scp> silicone rubber composites

Abstract

Abstract A novel and efficient flame retardant cyclophosphazene derivative Hexa ( p ‐acetamidophenoxy) cyclotriphosphazene (HACP) was successfully prepared via a facile one‐step reaction. The chemical structure of HACP was characterized and confirmed by FT‐IR, 1 H and 13 C NMR. Then the as‐prepared HACP was incorporated into addition‐cure liquid silicone rubber (ALSR) matrix to prepare highly flame‐retardant rubber composites. It was found that the incorporation of HACP can significantly enhance the flame resistance of ALSR. Typically, the ALSR composites filled with 30 phr HACP achieved UL‐94 V‐0 rating and meanwhile the total heat release and total smoke release were decreased by 26.9% and 41.5%, respectively. Moreover, the flame‐retardant mechanism of ALSR/HACP composites was investigated by TGA, Py‐GCMS, FT‐IR, SEM and EDX, confirming that HACP plays a significant role in capturing free‐radicals and forming protective layers. This work designed a novel cyclophosphazene‐based flame retardant to significantly enhance the flame retardancy of ALSR, which may offer some valuable inspiration for the fabrication of highly flame‐retardant polymer composites.