Smoke suppression and thermal conductivity of epoxy resin modified byAl2O3and hyperbranched flame retardant

Abstract

AbstractIn this work, aluminum oxide (Al2O3) was added to hyperbranched flame retardant (PTDOB) modified epoxy resin (EP) system to develop a novel EP thermoset (Al2O3‐PTDOB/EP) with superior comprehensive performance. Al2O3‐PTDOB/EP exhibited excellent flame retardancy, smoke‐suppressing effects, and enhanced mechanical properties due to the crack pinning effects caused by the introduction of Al2O3. In detail, the limiting oxygen index (LOI) and UL‐94 rating of Al2O3‐PTDOB/EP‐3 reached 34.6% and V‐0 rating, respectively. Cone calorimeter test showed that the total heat release, total smoke production (TSP) and average effective heat of combustion of Al2O3‐PTDOB/EP‐3 were reduced by 14.5, 27.3 and 19.2% in comparison to PTDOB/EP, respectively. Furthermore, the impact, tensile and flexural strengths of Al2O3‐PTDOB/EP‐3 were significantly improved by 16.7 28.4 and 10.7%, respectively, because the addition of Al2O3provided the carbon layer barrier and crack pinning effect for the EP matrix. Moreover, thermal conductivity of Al2O3‐PTDOB/EP was also improved due to the excellent thermal conductivity of Al2O3, which had broadened its application in the field of electronic packaging.