Synthesis of phospholipidated -cyclodextrin and its application for flame-retardant poly(lactic acid) with ammonium polyphosphate

In this study, phospholipidated -cyclodextrin (PCD) was obtained by the condensation between -cyclodextrin and phenyl phosphonic acid dichloride, which was characterized by Fourier transform infrared (FTIR) spectra, H-1-NMR, and thermogravimetric analysis (TGA). The thermal stability and flame retardancy of the poly(lactic acid) (PLA) blends [PLA-ammonium polyphosphate (APP)-PCD] were measured by TGA coupled to FTIR spectroscopy, vertical burning test (UL-94), limiting oxygen index (LOI), and cone calorimetry tests. The results show that the mass ratio and loading amount of APP and PCD affected the properties of PLA. When the loading of APP and PCD was 30 wt % and the mass ratio of APP to PCD was 5:1, the highest LOI value of 42.6% (that of neat PLA was 19.7%) and a UL-94V0 rating were achieved, and the reduction of the total heat release was greater than 80%. Even when the total amount of APP and PCD was decreased to 20 wt % with the same mass ratio, the flame-retardant PLA still can achieved a UL-94V0 rating. The improved performance was explained by the formation of an intumescent, continuous, contact char layer. Moreover, the reaction between APP and PCD contributed to the improvement of the thermal stability of the char residue. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46054.