Nanocomposites combustion peculiarities. A case history: Polylactide-clays

This paper addresses the combustion behaviour of polylactide (PLA) nanocomposites based on organomodified montmorillonite clays. It is shown that PLA nanocomposites burn in a very different way compared to virgin PLA. Indeed, nanocomposites burning rate is usually lower respect to PLA, with a rate decrease depending on clay type and concentration. However, an easier ignition is shown by PLA nanocomposites as compared to PLA which is due to a catalytic effect of the clays. It is shown that these peculiar features of nanocomposites burning behaviour may prevent reliable comparison between polymers and nanocomposites based only on a single parameter such as UL 94 test ranking or the Limiting Oxygen Index value (LOI). It is also shown that by an extended use of data provided by the LOI apparatus, the peculiarities of nanocomposites combustion process are easily detected.