Comparative Analysis of Dielectric Properties of Polyethylene and Polypropylene with Flame Retardants for Cables

Abstract

Modern sustainable cable insulation development increasingly emphasises recyclable materials, and widely used cross-linked polyethylene-based materials are often identified as problematic regarding low recyclability. Alternatives with better recyclability, such as polyethylene (PE) without cross-linking and polypropylene (PP), are being explored, particularly regarding their flame retardancy. This study evaluates the dielectricproperties of PE and PP filled with 5 wt% of aluminium hydroxide (ATH), magnesium hydroxide (MDH), or halloysite nanotubes (HNT). The characterisation and comparison of all tested materials were performed based on measurement of volume resistivity, dielectric strength, dielectric constant and dissipation factor. The volume resistivity of polymers decreased minimally with the addition of flame retardants, while the dissipation factorincreased, especially for HNT-filled polymers, but remained at an acceptable level. PE exhibited higher dielectric strength than PP, with MDH further enhancing this property in both materials, while ATH improved it only in PE. The tested filling level of ATH or MDH does not deteriorate the dielectric properties of PP and may even improve them, especially the dielectric strength; therefore, the tested PP-based composite becomes a viablealternative to conventional cable insulation materials.