Calcium carbonate (CaCO3/ is an abundant filler that is widely used
for cost reduction and to provide stiffness (rigidity) to the polyolefin
polypropylene (PP). It also has moderate beneficial effects on mechanical
properties such as an increase in modulus and impact strength.
Accordingly, it is worth examining the interactions of intumescent
flame-retardant (IFR) additives with CaCO3-filled composites. In this
context, inorganic fillers such as talc, CaCO3, and zinc carbonate do
not interfere with the intumescent process in filled polyamide-6 compounds,
yet they increase the thermal shielding efficiency of chars.1
Similarly, the presence of talc increased the fire-retardant performance
of ammonium polyphosphate-filled PP/polyamide-6/ethylene vinyl
acetate blends through char enhancement.2 However, a recent report
on the fire-retarding properties of intumescent PP composites found