Synergistic SiO2@DPPA flame retardancy for enhancing flame retardancy and thermal insulation in epoxy resin

<title>Abstract</title> <p> Novel and environmentally flame-retardant epoxy resin coating that maintain outstanding physical performance are urgently needed for high-tech fields. In this work, SiO ₂ @DPPA was successfully synthesized and incorporated together with SiO ₂ aerogel and OMMT into EP to prepare EP/SiO₂@DPPA composite coatings. Increasing the SiO ₂ @DPPA content progressively enhances the flame retardancy, with a 2wt% SiO ₂ @DPPA content yielding the optimal flame retardancy performance for EP. Compared to EP composite coating, the peak heat release rate (pHRR), total heat release (THR) and total smoke production (TSP) values of EP/SiO₂@DPPA composite coatings decreased effectively by 47.6%, 47.6% and 41.5%, respectively. The excellent heat and smoke reduction performance of the composite coatings was further validated through condensed and gas phase flame retardancy mechanism. Moreover, the EP/SiO₂@DPPA composite coatings has good mechanical properties, including the tensile strength of 11.1 MPa. This work further validates the feasibility of preparing flame-retardant high-performance polymer materials by adding organically modified SiO ₂ . </p>