Catalytic fire retardant nanocomposites

In this paper the chemical activity of carbon nanotubes and polyhedral oligomeric silsesquioxane during thermal degradation and combustion of polymer nanocomposites is addressed. Indeed, polymer-nanofiller systems may exhibit chemical effects capable of thermal stabilisation of polymers as well as reduction of combustion rate and heat released, owing to catalytic effects induced by the nanofillers; at high temperature. Carbon nanotubes in the presence of oxygen are shown to promote oxidative dehydrogenation in polyethylene with production of a stable surface layer of carbon char that provides an effective oxygen barrier effect. A similar action is performed by meta 1-containing polysilsesquioxanes dispersed in polypropylene. With either carbon nanotubes or metal POSS, partial carbonisation of the polymer matrix occurs during combustion, subtracting part of the organic polymer from combustion, targeting one of the major fire retardancy aim. (C) 2008 Elsevier Ltd. All rights reserved.