Short Communication: New Approach to the Dynamic Properties of an Intumescent Material

摘要

This work studies a polypropylene/ammonium polyphosphate/polyurethane intumescent fire retardant material. It reports the foaming expansion under a normal strain and the variation of the apparent viscosity of the heat-treated material measured using a plate-plate rheometer. The loss of the protective character of the intumescent coating is discussed. It is proposed that it is related to a limited foaming expansion value, an increase of its apparent initial viscosity and a decrease of this viscosity with time when a normal force and a sinusoidal strain are both applied. The changes in the dynamic properties of the system are explained by the chemistry of the intumescence process.