Intumescent polypropylene/flax blends: a preliminary study

This study deals with the effect resulting from the association of pentaerythritol with flax fibres in an intumescent PP/Fibre/ammonium polyphosphate/pentaerythritol/melamine system. This consists only in a preliminary to prove the efficiency of intumescent additives systems in polyolefin/flax composites considering the fire behaviour and the thermal stability of the material. The study confirms the Fire Retardance performances of a PP/flax/ammonium polyphosphate composite considering cone calorimeter data. Moreover, it shows that charring of the flax fibers in this composite does not give an interesting material in term of dynamic property. Using an intumescent model additive, we show that association of charring of the cellulosic material and of the intumescent system allows to obtain an optimized FR formulation.