The effect of some polymeric metal chelates on the flammability properties of polypropylene

A copolymer of acrylonitrile with N-(4-chlorophenyl)acrylamide was prepared and was reacted with ferric chloride, cobalt acetate and zinc acetate to obtain the corresponding metal chelates. The metal chelates were used with 16% kaolin as flame retardants for polypropylene. The flammability properties of the various polypropylene compositions were evaluated by thermogravimetric analysis (TGA) and cone calorimetry. It was found that the iron chelate showed the best synergistic effect with kaolin. This synergistic mixture reduced the average heat release rate of polypropylene by about 60% and the smoke emitted by 50%.