Flammability and anti-dripping behaviors of polylactide composite containing hyperbranched triazine compound

A hyperbranched derivative of trazine group (EA) and ammonium polyphosphate (APP) are incorporated into polylactide (PLA) in a constant amount. The component ratio effect of APP/EA on the flammability and anti-dripping property of PLA are investigated using the limiting oxygen index, vertical burning, and cone calorimetry tests. Results indicate that composite has the highest LOI value (41.2%) and the lowest peak heat release rate (139 kW/m2) when the mass ratio of APP/EA is 15/5. Meanwhile, UL 94 V-0 rating is achieved and no flammable dripping is observed. Residues are also investigated by scanning electron microscopy, Fouriertransform infrared, and X-ray photoelectron spectroscopy. Results demonstrate that a complete cross-linking reaction has occurred in PLA/15%APP/5%EA composite, which improves the melt strength and locks more chemical constituents containing carbon and nitrogen in the residues. Therefore, a dense, compact and intumescent char layer is formed.