Fire behavior of polyamide 12 nanocomposites containing POSS and CNT

Nanocomposites of polyamide 12 with multiwall carbon nanotubes (CNT) and octaisobutyl polyhedral oligomeric silsesquioxanes (POSS) were studied to assess their flame retardancy properties. The fire behaviour was investigated with a cone calorimeter using 50kW/m2 heat fluxes, by means of the oxygen index and the UL 94 H classification. The fire residue was characterized using FT-IR and SEM. The best overall performance was observed for the composites containing 3.3 wt% of POSS and 4 wt% of CNT. This composite achieved HB in UL 94, an oxygen index of 27 and a 74% reduction in the peak heat release rate. A synergistic effect was evidenced using POSS and CNT together whereas FT-IR and SEM analysis of the residue from fire experiments confirms the formation of SiO2 shield on the surface of the burning sample.