Structural studies on chars from fire retardant intumescent systems

The protection provided by intumescent chars against the action of the flame is generally attributed to their physical insulating properties. These in turn depend on the physical chemical structure of swollen char, which however has been scarcely studied. It is shown that scanning electron microscopy and microanalysis by energy dispersive system supply detailed information on the morphology and the chemical composition of intumescent systems. The data obtained contribute to the understanding of the fire retardance mechanism.