Synthesis of a single-component intumescent flame retardant and its high efficiency in imparting flame retardancy to polylactic acid.

In this paper, a single-component intumescent flame retardant di-(3-aminopropyltriethoxysilane) spirocyclic pentaerythritol diphosphate (PDAP) was synthesized, imparting flame retardancy to polylactic acid (PLA), which using melt blending process. The chemical structure and thermal stability of PDAP were characterized by test methods such as Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The fire retardancy of PLA/PDAP was evaluated by test methods such as limiting oxygen index (LOI) and vertical burning test (UL-94). The thermal stability of PLA/PDAP was studied by TGA and thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR). According to the results of laser Raman spectroscopy (LRS) and FTIR, the possible flame retardant mechanism of PLA/PDAP was discussed. With only 20 wt% addition of PDAP, PLA/PDAP could achieve 11.98% char residues at 800 °C. The LOI value of PLA/PDAP achieved 37%, UL-94 test reached V-0 rating. And higher fireproof performance with 62.1% reduced peak heat release rate (PHRR), 36.8% reduced total heat release rate (THR) and 19.5% reduced average effective combustion heat (av-EHC) value than PLA. The results show that PDAP has remarkable flame retardant effect on PLA, which provides an excellent research case for flame retardant modification of PLA plastic products. [ABSTRACT FROM AUTHOR]