Abstract: Three intumescent flame retardant, KDIFR, MAPP, and APP were introduced separately into epoxy resin (EP) and their effects were compared. Limiting oxygen index and horizontal burning test showed that APP had the best flame retardancy behavior among the three. When the mass ratio of APP/EP was 0.3, the limiting oxygen index reached 32.2 %. The flame retardancy property of EP/APP could be further improved by introducing either aluminum or boron, or better the both. When the content of aluminum borate was 0.8 wt % of APP, the self-extinguishing time of EP/APP decreased to 24 s from 48 s. Thermal analysis indicated that heat absorbed during the thermal decomposition of APP nearly equal to that released during the thermal degradation of EP, which was the main reason for APP's good behavior. The char yield of EP/APP was promoted obviously when introducing aluminum and boron in the EP/APP composite.

Key words: aluminum, composite, flame retardancy, epoxy resin, intumescent flame retardant, ammonium polyphosphate, boron, influencing factor