Pyrolysis and fire behavior of high impact polystyrene (HIPS) containing red phosphorus and melamine polyphosphate were investigated. The thermal and thermo-oxidative decomposition were characterized using thermogravimetry coupled with FTIR and MS, respectively. The fire behavior was monitored with a cone calorimeter using different external heat fluxes and determining the LOI. Red phosphorus reduced the heat release in HIPS due to radical trapping in the gas phase. The reduction in effective heat of combustion was accompanied by an increase of incomplete combustion products such as smoke and carbon monoxide. Melamine polyphosphate in HIPS acted in the condensed phase with barrier formation. The heat release rate was reduced, whereas the total heat evolved, smoke and carbon monoxide formation were not influenced significantly. Using both fire retardants, the resulting fire retardancy was characterized mainly by superposition.
Polymeric nanocomposites are discussed as one of the most promising advanced materials whose nanoscale effects can be exploited for industry. Layered silicate polypropylene-graft-maleic anhydride nanocomposites are investigated as a model to clarify the potential of such materials in terms of fire retardancy. The nanostructure is characterized using transmission electron microscopy (TEM) and shear viscosity. The fire behavior is characterized using different external heat fluxes in cone calorimeter, limiting oxygen index and UL 94 classification. A comprehensive fire behavior characterization is presented which enables an assessment of the materials’ potential with respect to different fire scenarios and fire tests. The influence of morphology and the active mechanisms are discussed, such as barrier formation and changed melt viscosity. To our knowledge, it is the first attempt to illuminate the concept’s strengths, such as the reduction of flame spread, and weaknesses, such as the lack of influence on ignitability, in a clear, comprehensive and detailed manner.