Study On Flame Retared EVA

The flame retardant properties of EVA with new-style intercalation nanocomposites and conventional flame retardant were studied using the cone calorimeter and LOI techniques. The aim is to discuss applicable e retardant techniques in cable product and relevant mechanism.The XRD analyses show that positive ion exchanges react between sodium-montmorillonite(Na~+-MMT) and organic ammonium salt. Then the spacing between the layers of Na~+-MMT was expanded to form organic montmorillonite(OMMT). EVA and OMMT can form nanocomposites by melt intercalation. A higher OMMT content does not have effect on layer construction. EVA and MMT can not form nanocomposites directly.The microcosmic configurations of surface and transect of the EVA/OMMT burnt char are observed by SEM. The shape of silicate layers are clear and can be a barrier to combustion.The cone calorimeter is used to measure the flammability parameters. The heat release rate(HRR) show that EVA/OMMT has a much lower HRR compared to EVA and EVA/MMT. The effective heat of combustion(EHC) of EVA/OMMT is also lower than that of EVA. EVA and MMT can not form intercalation composites. The mass change curves show that the mass retain rate is higher of that of EVA/MMT and EVA/OMMT in the early combustion stage due to the volatilization of the ammonium salt and impurities. Along with the combustion, the mass...