Fire retardant properties of chicken feather/TPU composites containing phosphorus fillers

The aim of this study was to enhance the flame-retardant properties of chicken-feather-reinforced thermoplastic polyurethane (TPU) composites by incorporating three different phosphorus-based flame retardants - namely, aluminum hypophosphite (AHP), ammonium polyphosphate (APP) and aluminum diethyl phosphinate (AlPi) - at concentrations of 5, 10 and 20 wt%. The effectiveness of the additives was evaluated through various tests, including limiting oxygen index test, vertical burning test (vertical UL 94), thermogravimetric analysis and mass loss calorimeter test. The results indicated that all three additives exhibited flame-retardant properties in both the condensed and gas phases, but APP and AHP performed better than AlPi due to their enhanced char-formation capabilities. The flame-retardant effectiveness of the additives decreased in the order of APP > AHP > AlPi.