Linear low density polyethylene (LLDPE) compounds containing 10 wt.% graphite fillers were
rotationally molded into flat sheets. Flame retardancy was studied using cone calorimeter tests
conducted at a radiative heat flux of 35 kW m2. Only the expandable graphite, an established flame
retardant for polyethylene, significantly reduced the peak heat release rate. Compared to the neat
polyethylene, it was easier to ignite the LLDPE composites containing carbon black, expandable
graphite and exfoliated graphite. However, rather unexpectedly, the inclusion of flake graphite
increased the time to ignition by up to 80%. Simulations conducted with the ThermaKin numerical
pyrolysis software suggest that increased reflectivity was mainly responsible for this effect.