Thermal Evolution of Nanocomposites. When Nanoparticles are Effective in Polymer Fire Retardancy

A decade of research and development concerning polymer nanocomposites has shown the essential features of their combustion process. Nanocomposites actually display a fire retardant behaviour because they avoid fire propagation by dripping of hot and flaming polymer particles and reduce the rate of combustion. The mechanism involved in nanocomposites fire retardance is based on formation on heating of a ceramic protective, insulating layer on the surface of the burning material resulting from coalescence of nanofillers enclosing char from surface polymer charring, catalysed by the nanofiller. The thermal evolution of nanocomposites to the fire protective structure is discussed in relation with dispersion and distribution of the nanofillers in the polymer matrix either as it results from nanocomposite preparation or from its thermal evolution. Evaluation of the fire retardant performance of polymer nanocomposites in fire tests representing different fire scenarios (i.e. ignition, flammability and forced combustion) will be discussed in this talk.