TY - JOUR A1 - Langfeld, Kirsten A1 - Wilke, Antje A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Ulmer, B. A1 - Andrievici, V. A1 - Limbach, P. A1 - Bastian, Martin A1 - Schartel, Bernhard T1 - Halogen-free fire retardant styrene-ethylene-butylene-styrene-based thermoplastic elastomers using synergistic aluminium diethylphosphinate-based combinations JF - Journal of fire sciences N2 - Multicomponent flame retardant systems containing aluminum diethylphosphinate in thermoplastic styrene–ethylene–butylene–styrene elastomers are investigated (oxygen index, UL 94, cone calorimeter, and mechanical testing). Solid-state nuclear magnetic resonance, scanning electron microscopy, and elemental analysis illuminate the interactions in the condensed phase. Thermoplastic styrene–ethylene–butylene–styrene elastomers are a challenge for flame retardancy (peak heat release rate at 50 kW m-2 > 2000 kW m-2, oxygen index = 17.2 vol%, no UL-94 horizontal burn rating) since it burns without residue and with a very high effective heat of combustion. Adding aluminum diethylphosphinate results in efficient flame inhibition and improves the reaction to small flame, but it is less effective in the cone calorimeter. Its efficacy levels off for amounts >~25 wt%. As the most promising synergistic system, aluminum diethylphosphinate/melamine polyphosphate was identified, combining the main gas action of aluminum diethylphosphinate with condensed phase mechanisms. The protection layer was further improved with several adjuvants. Keeping the overall flame retardant content at 30 wt%, aluminum diethylphosphinate/melamine polyphosphate/titanium dioxide and aluminum diethylphosphinate/melamine polyphosphate/boehmite were the best approaches. An oxygen index of up to 27 vol% was achieved and a horizontal burn rating in UL 94 with immediate self-extinction; peak heat release rate decreased by up to 85% compared to thermoplastic styrene–ethylene–butylene–styrene elastomers, to <300 kW m-2. KW - Flame retardancy KW - Aluminium phosphinate KW - Thermoplastic elastomers KW - Cone calorimetry KW - Flammability PY - 2015 DO - https://doi.org/10.1177/0734904114565581 SN - 0734-9041 SN - 1530-8049 VL - 33 IS - 2 SP - 157 EP - 177 PB - Sage CY - London AN - OPUS4-32692 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -