Dielectric behaviors of recyclable thermo-plastic polyolefin blends for extruded cables

XLPE, which exhibits good electric insulation and mechanical properties due to its chemical crosslinked structure, has been used as modern extruded cable insulation materials for nearly 60 years. However, XLPE cannot be easily recycled in the end of its lifetime so that there will be a big issue in dealing with XLPE craps. New polyethylene blending materials, which have suitable recyclability and comparable dielectric and mechanical properties with XLPE, is gaining increasing attention. In this investigation, dielectric behaviors of a new blending material have been compared with XLPE. This new blend contains liner low-density polyethylene as matrix and high-density polyethylene as blending. XLPE, pure liner low-density polyethylene and high-density polyethylene are also prepared and tested for comparison. DC resistivity, permittivity, loss tangent and breakdown strength of these materials are measured at 30°C, 45°C 60°C, 75°C, 90°C respectively. The temperature dependence of dielectric properties for these systems has been measured and discussed. The results show that temperature dependence of DC resistivity, permittivity for these materials present the similar tendency. However, the new thermo-plastic polyolefin blends show lower loss tangent and higher breakdown strength than XLPE especially the loss tangent at high temperature. The results suggest that the blend has a great potential to be used for extruded cables.