High‐Efficiency Flame‐Retardant Epoxy Composites via Synergistic Heat Dissipation and Moisture Release Effects

ABSTRACT Epoxy resin (EP) composites with low cost and high flame retardancy were fabricated by incorporating powdered activated carbon (PAC) and aluminum hydroxide (ATH) as flame‐retardant fillers. The composites were prepared using a conventional melt‐mixing and curing process with diglycidyl ether of bisphenol A (DGEBA) and hexamethylenediamine (HMDA) as the epoxy and hardener, respectively. Flame‐retardant performance was evaluated using cone calorimetry, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The EP composite containing 40 wt% PAC and 10 wt% ATH (denoted as EP/PAC40/ATH10) exhibited a 50% reduction in peak heat release rate (PHRR) from 474.4 to 239.0 kW/m 2 , and a 61% decrease in total heat release (THR) from 63.2 to 24.8 MJ/m 2 compared to neat EP. Total smoke production (TSP) also decreased by 55%, from 16.2 to 7.3 m 2 . Furthermore, the char yield at 800°C increased from 6.3% (neat EP) to 48.7% (EP/PAC40/ATH10), confirming improved thermal stability. The thermal conductivity of the EP/PAC40/ATH10 composite was 0.63 W/m K, more than double that of neat EP (0.21 W/m K). These results indicate that the combined use of PAC and ATH enhances the flame retardancy, smoke suppression, and heat dissipation of EP composites, providing a promising solution for fire‐safe epoxy applications.