Effect of N,N′-diallyl-phenylphosphoricdiamide on ease of ignition, thermal decomposition behavior and mechanical properties of poly (lactic acid)

In this study, a novel poly (lactic acid) (PLA) composite with low flammability based on N,N′-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 kinetics 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.