Effect of composition on ablative properties of epoxy composites modified with expanded perlite

The present work investigates ablative and thermoprotective properties of epoxy resins modified with expanded perlite (vermiculite - 3% or 10% of weight share). The properties of two epoxy resins (Epidian 52 and Epidian 601 cured with triethylenetetraamine - hardener Z-1 or cured with hardener TFF - triethylenetetraamine with phenol) were studied. Statistical methods for planning experiments were used and the effect of components on thermoprotective properties of epoxy composites was established. The maximal temperature of the rear surface of an ablative sample and an average relative ablative (erosive) mass loss after 120 s of the heat flux exposition were analysed. It was shown that the best of both thermoprotective properties, i.e. low temperature of the rear surface area and low ablative mass loss (the highest thermal stability), were achieved by the composite based on Epidian 601 cured with hardener Z-1 and containing 10% mass of vermiculite. More stabilized ablative layer with limited erosion was obtained with a higher vermiculite participation (especially with Epidian 52 + TFF). Moreover, the type Z-1 of epoxy hardener showed the most significant effect on the maximum temperature of the rear surface area. Triethylenetetraamine hardener Z-1 decreases this temperature.