BCC 2011 Thermal Evolution of Nanocomposites. When Nanoparticles are effective in polymer fire retardancy

摘要

It is generally agreed that the combustion behavior of polymer nanocomposites strictly depends on the interface between polymer condensed phase and the gas phase. Since the first studies on the nanocomposites' behavior in fire [1,2], it was pointed out that the behavior under forced combustion for different nanocomposites were quite similar: a reduction of the heat release rate consequent to a lower fuel feed rate often without substantial modifications of the polymer bulk degradation pathway. Such a behavior is related to the formation of a physical shield built up by the inorganic nanoparticles left behind by polymer ablation, which acts as a barrier, slowing down the release of generated gas fuel. However, limited understanding of fundamental of physical and chemical process occurring in the condensed phase is available at present. Indeed, complex phenomena can take place in the surface mesophase during nanocomposite burning, affecting accumulation of inorganic particles and their interaction with the polymer while building of a surface structured ceramic phase takes place. Furthermore, the effectiveness of these phenomena on the fire performance of the nanocomposite strictly depends on the specific features of the considered test, such as geometrical setup, presence or absence of external heating source and the possibility of dripping.