New insulating material technologies for high transfer and sustainability

Cross-linked polyethylene (XLPE) remains the primary insulating material employed in cable applications; however, it presents several limitations, including its inability to be recycled, the substantial energy demand associated with the crosslinking process, and the complexity of its manufacturing procedures. Therefore, isotactic polypropylene (iPP) is chosen as a thermoplastic alternative to replace XLPE in power cable insulation applications. As one of the most widespread engineering polymers, iPP has been considered in applications such as packaging, textiles and automobile industries long before it was considered in the cable industry. Its main disadvantage has historically been its high brittleness which has begun being addressed over the past 40 years with the addition of elastomers [1]. More specifically, since electrical and thermal performance is also crucial in the cable industry, some of the main challenges in the use of iPP, (also identified in the WP3.2 report) are: · High mechanical modulus and brittleness (at room temperature) · Formation of large spherulites · Low thermal conductivity Addressing these challenges necessitates material modifications such as blending with assorted elastomers, as well as other additives. These strategies will be reviewed in the following sections.