Layered silicate polymer nanocomposites: new approach or illusion for fire retardancy? Investigations of the potentials and the tasks using a model system

Polymeric nanocomposites are discussed as one of the most promising advanced materials whose nanoscale effects can be exploited for industry. Layered silicate polypropylene-graft-malefic 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. Copyright (C) 2004 John Wiley Sons, Ltd.