Synergies between phosphomolybdate and aluminum diethylphosphinate acting as temperature-response microparticles for promoting fire safety of epoxy resin

Abstract

In this work, ammonium phosphomolybdate (AMP) and aluminum diethylphosphinate (ADP) acting as temperature-response microparticles, were incorporated into epoxy resin (EP) together to promote fire safety and dynamic mechanical performance of EP composites at the same time. Both ADP and AMP acted as chemical inertness fillers to enhance the EP matrix at the normal service temperature and processing temperature. When the temperature rose after heating or even burning, both ADP and AMP presented chemical functions. On one hand, AMP exhibited excellent catalytic charring activity and smoke suppression efficiency. On the other hand, the combination between AMP and ADP in the EP/AMP/ADP composites showed excellent synergistic effects in improving the flame retardancy of EP. Compared to the case of EP, the peak heat release rate (PHRR) of EP/AMP/ADP composites (1.2 wt% AMP and 3.6 wt% ADP) was decreased by 54%, the total heat release (THR) was reduced by 25%, and the total smoke production (TSP) was reduced by 25%. Meanwhile, the UL-94 V-0 rating was obtained, and the limiting oxygen index (LOI) of the composite was increased from 26.2 to 31.2%. The mechanism of flame retardancy was analyzed and discussed. In addition, compared with EP, EP/AMP/ADP composites showed a higher dynamic mechanical property without affecting the glass transition temperature.