The effects of filler size and content on the fire behavior of melt-spun poly(lactic acid)/cellulose bionanocomposite fibers

Nanoscale reinforcements have strong promise in designing ecofriendly green bionanocomposites by combining (natural/bio) fibers with biodegradable polymers. However, the poor fire resistance of these organic materials restricts their applications in some industrial fields such as the textile, electric and electronics industries. Indeed, the textile industry is probably the first ones to point out the durability of flame retardancy as a major issue. In this paper, fibers of poly(lactic acid)/cellulose nanowhiskers (PLA/CNW), and poly(lactic acid)/cellulose microcrystalline (PLA/MCC) were prepared by melt spinning at filler content of 1 and 3 wt%, in the presence of 7 wt% of PLA-grafted-maleic anhydride (PLA-g-MA) used as the compatibilizer. The flame retardancy properties of the samples were investigated by Pyrolysis Combustion Flow Calorimeter (PCFC) test. The results showed that the addition of MCC and CNW to PLA fibers led to the formation of a protective char layer, which protects the bionanocomposite sample from the action of heat flux and flame during combustion. Furthermore, the incorporation of 1 wt% of CNW to PLA resulted in better flame retardancy properties than MCC due to better morphology as well as dispersion of CNW in the polymer.