Highly-effective Flame Retardancy of Poly(lactide) Composite Achieved Through Incorporation of Amorphous Nickel Phosphate Microparticle

Abstract In this study, amorphous nickel phosphate (NiPO) was prepared through urea-assisted hydrothermal process. The composition of NiPO was investigated via X-ray photoelectron spectrum (XPS). And the structure of NiPO was characterized by Fourier transform infrared spectrometer (FTIR) and X-ray diffraction measurement (XRD).Then poly(lactide) (PLA) was melt blended with the resulting NiPO to prepare flame retardant PLA composites. The flame retardant property of PLA composites was probed using limiting oxygen index test (LOI), UL-94 vertical burning test (UL-94), cone calorimeter test (CCT). And the thermal combustion property was analyzed through pyrolysis combustion flow calorimeter test (PCFC). In the meantime, the thermal stability of NiPO microparticles and PLA composites was analyzed through thermogravimetric analyzer (TGA) and integrated procedural degradation temperature (IPDT). In the meantime, the melting and crystallization property of PLA composites was investigated through DSC analysis. Results showed that NiHPO3 was the main component of NiPO. PLA composite with only 2 wt.% NiPO powder exhibited excellent flame retardancy (LOI = 27.5% and UL-94 V-0 rating). In the CCT and PCFC test, it showed that HRR of PLA composites was higher in the early stage of combustion and lower in the late stage of combustion than that of pure PLA. Moreover, a slightly increased CO production rate (COP) and obviously decreased total smoke production (TSP) were found in PLA composites containing 2 wt.% NiPO in CCT. In the DTG curve, the similar weight derivation trend to HRR in CCT and PCFC test was also observed. Additionally, the intrinsic thermal stability was enhanced significantly by 19°C with 2 wt.% NiPO into PLA composites. DSC results showed that NiPO could also improve the crystallization property of PLA composites. Keywords: Amorphous nickel phosphateHigh-effective flame retardancyPLA composites Notes a The cotton could be ignited by the dripping. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lpte.