A mechanistic study of fire retardancy of carbon nanotube/ethylene vinyl acetate copolymers and their clay composites

A further investigation of the roles of multi-walled carbon nanotubes and clay in the fire retardancy of ethylene vinyl acetate copolymer (EVA) nanocomposites has been carried out. It was found that the nanotubes played an important role in the reduction of the peak of heat release rate by forming low permeability char containing graphitic carbon. The oxidation resistance of the char is a function of the degree of graphitisation. Adding clay into the nanotube/EVA composite tends to enhance the formation of graphitic carbon. The nanotubes also have the function of reducing surface cracks of chars to increase barrier resistance to the evolution of flammable volatiles and the oxygen ingress to the condensed phase.