Posted on 06/07/2020 in Fire Safety 2020
Aluminium – APP synergy

Inclusion of aluminium oxide in polyester with PIN FR ammonium polyphosphate (APP) improved fire performance and mechanical properties. Three different metal oxides (Al2O3, Fe2O3 and Sb2O3) were tested as synergists at 0.5 to 5% in PIN flame retarded unsaturated polyester resin (70% resin / 30% APP or APP plus metal oxide). APP alone or with metal oxides enabled pass of UL94-V0 (3 mm) vertical burn test and reduced smoke emission significantly (peak smoke reduced by nearly one third). All three metal oxides increased LOI (limiting oxygen index: c. 20 for pure polyester resin, 36 with APP alone, 41 with 0.5% Al2O3) but tin oxide increased total heat release. Aluminium oxide is identified at the best flame retardant synergist with APP (in polyester resin as tested) and also 0.5% Al2O3 showed better mechanical properties than APP alone.

“Enhanced flame retardancy of unsaturated polyester resin composites containing ammonium polyphosphate and metal oxides”, W. Gao et al., J Appl Polym Sci. 2020 e49148

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