Fire retardant electrically conductive composite materials based on polyethylene

The article presents the results of research on electrically conductive hard-to-burn composite materials based on polyethylene, graphite, and some flame retardants. It is shown that optimal electrical conducting properties and the flammability rating (V0) in accordance with UL 94 test are achieved by modifying the graphite-containing composite material based on low-pressure polyethylene with ammonium polyphosphate and (or) aluminum hydroxide. It is shown that the percolation threshold of a composite material based on high-pressure polyethylene and graphite is observed at significantly higher values of the mass fraction of graphite. It is concluded that the reduction of the percolation threshold of polyethylene when filled with graphite is facilitated by an increase in the degree of crystallinity of the binder, and the formation of structured continuous conducting clusters in the composite material is observed at lower values of the mass fraction of the filler. As a result, the thermal conductivity and heat resistance of the composite material are increased owing to more efficient delocalization of the supplied heat. A number of electrically conductive hard-to-burn materials were obtained and characterized. These data allow us to directly adjust the values of the specific volume electrical resistance, physical and mechanical properties, heat resistance, and, to a certain extent, flame resistance.