Role of montmorillonite for enhancing fire retardancy of intumescent PLA

This work deals with the effect of an organomodified montmorillonite (OMMT, cloisite C30B) in intumescent PLA, which makes it nonflammable. The use of OMMT dramatically improves the fire properties of intumescent PLA in terms of limiting oxygen index (LOI) and heat release rate (HRR), which is almost zero. The part played by OMMT in the improvement of the FR performance was studied using a Microscale Combustion Calorimeter (MCC), solid-state NMR (13C, 31P and 27Al) and specific set-up for temperature and swelling measurements in the char during fire test. It is shown that the clay increases the efficiency of the protective char by strongly limiting heat and mass transfer.