A Rational Interface Engineering Approach for Ternary Polypropylene Blends with Superior Mechanical and Electrical Insulation Properties

Polypropylene (PP) has emerged as a promising alternative to cross-linked polyethylene (XLPE) for power cable insulation due to its recyclability, superior thermal stability, and simple manufacturing process. However, PP-based insulation materials have great challenges including limited toughness and low impact strength at low temperatures in the application of power cables. In this work, the delicate structural design of multicomponent elastomers was proposed to simultaneously enhance the mechanical, electrical, and thermal properties of PP-based insulation materials by incorporating two elastomers: propylene-based elastomer (PBE) and styrene–ethylene–butadiene–styrene (SEBS). A unique strawberry-like structure, where the PBE phase was dispersed between SEBS and the PP matrix, was successfully constructed to enhance interfacial compatibility and promote stress dissipation. As a result, the as-prepared PP-based ternary blends exhibited a tensile ductility of 653%, an alternating current breakdown strength of 31.2 kV·mm–1, and thermal elongation below 3%, reaching the stringent performance requirements for power cable insulation. The work presented here opens up an effective avenue to develop sustainable, high-performance PP-based insulation materials via elastomer compounding, offering a promising alternative to traditional XLPE for power cable applications.