Smoke suppression and thermal conductivity of epoxy resin modified by Al2O3 and hyperbranched flame retardant

In 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 Al2O3 provided 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.

Automated summary

A novel EP thermoset, Al2O3-PTDOB/EP, was developed in this study by adding aluminum oxide to hyperbranched flame retardant modified epoxy resin system, exhibiting superior comprehensive performance including excellent flame retardancy, smoke-suppressing effects, and enhanced mechanical properties.