Flame-Retardant Properties of PP/Al(OH)3/Mg(OH)2/POE/ZB Nanocomposites

The flame-retardant composites of polypropylene (PP) were prepared using a twin-screw extruder by compounding PP with either aluminum hydroxide (Al(OH)(3)), magnesium hydroxide (Mg(OH)(2)), zinc borate (ZB), polyolefin elastomer(POE) and nanometer calcium carbonate (nano-CaCO3). The flame retardant properties of these composites, including oxygen index (OI), horizontal burning speed (V), and smoke density rank (SDR) were measured. The results showed that the OI increased linearly, while the V and the SDR decreased nonlinearly with an increase of the filler weight fraction, and the effect of the specimen thickness on the V was significant. The reduction of the V of the flame-retardant PP composites decreased with increasing the specimen thickness. The addition of the nano-CaCO3 and POE could improve the flame-retardant properties of the composites.