The use of Weibull modulus for the polypropylene based polymer blends as cable insulation material

The growing demand for recyclable and high-performance insulation materials in power cable systems has motivated the search for alternatives to cross-linked polyethylene (XLPE). This study investigates the potential of polypropylene (PP)/polyethylene (PE)-based polymer blends, modified with ethylene propylene diene monomer (EPDM), as viable substitutes for traditional insulation in low and medium voltage cables. Thirteen different polymer blend formulations were synthesized and characterized using tensile testing, with statistical analysis performed via the two-parameter Weibull distribution to assess the reliability of mechanical performance. Additionally, two processing methods—injection molding only (blending + plasticizing) and a combination of extrusion (blending) and injection molding (plasticizing)—were evaluated for their impact on process durability and processing efficiency. Among these, the blend containing 40% EPDM, 30% PP, and 30% PE, processed by extrusion followed by injection molding, achieved the highest Weibull modulus (37.1), tensile strength (15.8 MPa), and elongation at break (696%). Prototype cables manufactured with this blend were further evaluated by mechanical, thermal aging, water absorption, shrinkage, and electrical resistance tests according to TS IEC 60,502-1. The optimized blend showed superior performance compared to XLPE, PE, and PVC, with electrical resistivity values exceeding 6 × 10 12 Ω·cm and fracture strain values three times higher than commercial sheathing. This is the first study to integrate Weibull statistical analysis with real-scale prototype validation of PP/PE/EPDM blends, demonstrating their scalability as a recyclable and reliable alternative to XLPE in low- and medium-voltage cable insulation.