1 Introduction
The cross-linked polyethylene (XLPE) is widely applied as insulating materials in high voltage cables. However, as thermosetting material, XLPE is difficult to recycle at the end of lifetime [1]–[5]. The recyclable blend of PP and POE has attracted much attention. It not only modifies the brittleness and stiffness of pure PP, but also shows many outstanding performances in electrical and thermal properties. In addition, it can be manufactured without the crosslinking step, reducing much time and energy consumption. With these unique advantages, the PP/POE blend has been considered as a potential HVDC cable insulating material to replace XLPE in the future [6]–[9].