Emerging advancements in flame retardancy of polypropylene nanocomposites

Polypropylene (PP) burns very rapidly due to its wholly aliphatic hydrocarbon structure. Studies have shown that the rapid decomposition and flammability of PP are very high when compared with wood and other cellulosic materials. This has limited the application of PP and necessitated the need to inculcate flame-retardant (FR) behaviour to PP to further widen its scope of application especially in areas where FR is paramount. With the advent of nanotechnology, increasing inclusion of FR nanofillers in PP has demonstrated propensity to repressing critical flammability parameters such as heat release rate, peak of heat release rate, rate of carbon monoxide production, smoke production rate and total mass loss rate while simultaneously increasing limiting oxygen index, time of ignition and total peak of heat release rate. This efficiently represses PP flammability and provides greater opportunity to minimize loss and risks to life in actual fire scenario through creation of equal layers of carbonaceous char in the condensed phase capable of suppressing the thermal decomposition caused by oxygen and heat to PP matrix, thus effectively cutting-off the fire path. This article reviews recent developments in FR of PP composites, nanocomposites and nano-biocomposites. Market structures are also presented.