A study of γ-radiation-crosslinked HDPE/EPDM composites as flame retardants

The dynamic flammability of flame-retardant composites that consist of high-density polyethylene (HDPE) and ethylene-propylene-diene rubber (EPDM) and other additives, and can be used as wire- and cable-insulation materials, was studied before and after irradiation. The data for the heat-release rate (HRR), the time to ignition, the specific extinction area and the concentrations of CO and CO2 from the burning process of cone colorimeter tests were assessed. By blending HDPE with EPDM, the HRR of HDPE was reduced and the residue char of the composite increased. The HRR of HDPE/EPDM was further reduced and the residue char of HDPE/EPDM was further increased after irradiation. The oxygen index, mechanical properties, and thermal stability of the composites, and the morphology of the char formed in the cone calorimeter test, were also investigated. (C) 2004 Society of Chemical Industry.