Improving Epoxy Resin Performance with Sepiolite and Al<sub>2</sub>O<sub>3</sub>- Doped Sepiolite: Flame Retardancy and Thermal Stability

The sepiolite and Al 2 O 3 -doped sepiolite contents in the as-received sepiolite/epoxy systems were maintained at 2 and 4wt %, respectively. The flame-retardant capabilities and combustion behavior of Al 2 O 3 -doped sepiolite in epoxy resin were meticulously evaluated through a series of tests including cone calorimetry (CC), limiting oxygen index (LOI), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Several features, including degradation kinetics, combustion characteristics, thermomechanical properties, flame retardancy, and thermal degradation were evaluated with the intention of drawing comparisons to standard sepiolite. The findings from the studies were positive. In contrast, Al 2 O 3 -doped sepiolite not only further improved the LOI values and char formation post-cone testing but also decreased the previously mentioned combustion-related parameters in the composites. A potential synergistic interaction between sepiolite and Al 2 O 3 in augmenting the flame retardancy of the composite was suggested. The thermal degradation of composites was only little affected by addition of sepiolite, although Al 2 O 3 -doped sepiolite addition seemed to speed up the deterioration process. The epoxy composite’s glass transition temperature (Tg) was shown to increase when sepiolite or Al 2 O 3 -doped sepiolite was added, as determined by DMA. The findings presented in this research provided a practical approach to improving the fireproofing of polymers. Keywords: Al2O3-doped sepiolite; TGA, flame retardancy; DSC, epoxy; thermal properties.