In Situ Preparation of <scp>DOPO</scp> Functionalizing Boron Nitride for Epoxy Resin With Improved Flame‐Retardant and Thermally‐Conductive Properties

ABSTRACT The rapid advancement in microdevice and integrated circuit technology had precipitated significant thermal failures and elevated fire risks for epoxy resin (EP). In order to simultaneously enhance the flame‐retardant and thermal conductivity performance of EP, biomass phytic acid was used to modify boron nitride (BN) to obtain BNA, and then 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was used to functionalize BNA in order to prepare functionalized BN with excellent flame retardancy and good thermal conductivity. FT‐IR, SEM, and TGA were used to characterize the functionalized BN. The EP composite with 15 wt % functionalized BN (EP/15% FBN) exhibited a UL‐94 V‐0 rating and a LOI of 35.3%. The peak heat release rate, total heat release rate, and total smoke production of EP/15% FBN decreased by 47.6%, 44.7%, and 19.8%, respectively, compared with those of EP. The mechanical properties of EP/15% FBN were enhanced compared with those of EP. Additionally, a 150% enhancement in thermal conductivity was observed for EP/15% FBN, which was attributed to the decreased interfacial thermal resistance. The enhanced flame retardation of the EP composites primarily resulted from the creation of a stable char layer. Consequently, the flame‐retardant modified BN offered a novel approach for developing flame‐retardant and thermally conductive EP composites.