In this study, a superefficiently flame-retardant bioplastic poly­(lactic acid) was developed by incorporating gas–solid biphase flame-retardant N,N′-diallyl-P-phenylphosphonicdiamide (P-AA), into PLA matrix. The flame retardancy of PLA/P-AA was investigated by limiting oxygen index (LOI), vertical burning test (UL94), and cone calorimeter test. Surprisingly, it was noted that only 0.5 wt % loading of P-AA increased LOI value of PLA from 20.5 to 28.4 and passed UL 94 V-0 rating at 3.2 mm thickness. In order to understand the effect of P-AA on the thermal decomposition behavior of PLA, a comprehensive study was investigated in this paper, including (i) adopting modified Coats–Redfern method to study the thermal decomposition kinetics of PLA and PLA/P-AA systems, and (ii) characterizing the evolved gaseous products and the residues in the condensed phase by thermogravimetry linked Fourier transform infrared spectroscopy (TGA–FTIR) and variable temperature Fourier transform infrared spectroscopy (VT-FTIR) techniques, respectively. Moreover, tensile properties of PLA and PLA/P-AA were studied.

In this study, a novel poly (lactic acid) (PLA) composite with low flammability based on N,N 0 diallyl phenylphosphoricdiamide (PO AA) and PLA was developed via traditional melt compounding. PO AA exhibited high efficiency on reducing the ease of ignition of PLA without scarifying the mechanical and thermal properties of PLA. Only 1 wt% of PO AA containing PLA composite passed V 0 rating with 3 2 mm (thickness of the specimen), while 2 wt% of PO AA addition made PLA passed V 0 rating with thickness of 1.6 mm. The improvement also performed on increased limiting oxygen index (LOI) of PLA composites. The melting and crystallization behavior of PLA and PLA/PO AA composites were studied by differential scanning calorimetry (DSC). Meanwhile, thermal stability and thermal decomposition ki netics were studied by means of thermogravimetric analysis (TGA). Furthermore, the evolved gaseous products of PLA and PLA/PO AA (1 wt%) were characterized by TGA coupled with Fourier transform infrared spectroscopy (TGA FTIR) test. Finally, the impact of PO AA on viscoelastic and tensile properties was investigated by dynamic oscillatory shear measurement and tensile test.