Flame retardant effect of aluminum phytate in huntite–hydromagnesite filled plasticized poly(lactic acid) compounds

In the current study, aluminum phytate (AlPt) is used with huntite–hydromagnesite (HH) in plasticized poly(lactic acid) (PLA) in order to improve the fire-retardant performance of the composite. The flame retardant, thermal, and mechanical properties of the composites are investigated using the limiting oxygen index (LOI), horizontal and vertical burning test (UL-94), mass loss calorimeter, thermogravimetric analysis, tensile, and impact tests. According to the test results, the fire-retardant performance of the composite was improved when HH and AlPt were used together. The highest LOI value (33.8) and UL-94 rating of V0 were achieved with the addition of 5 mass% AlPt in the presence of 55 mass% HH. Further, the addition of AlPt did not change the flammability properties. AlPt showed its adjuvant effect predominantly in the condensed phase via improved char formation with enhanced barrier properties. Tensile and impact strength reduced as the added amount of AlPt increased due to the hydrolytic degradation of PLA during the extrusion process.