Influence of talc on the fire retardant properties of highly filled intumescent polypropylene composites

Intumescent systems have been developed since many years for a wide range of applications, even if they are mainly used in coatings nowadays. The objective of this paper is to determine if the intumescent concept can be applied to highly filled reinforced polypropylene (PP) composites containing talc. Formulations that meet the electrical industry requirements have been developed, even if it has been observed that the addition of talc into intumescent PP leads to a decrease in the fire retardancy of the systems. A thermal stabilization of the material is noted at high temperature in the presence of talc. An increase in the crystallinity of the intumescent structure is suspected to be, at least partially, responsible for the decrease in the performance.