Effects of Surface‐Treated Nanomagnesia on the Electro‐Mechanical Properties of Polypropylene/Ethylene‐Propylene‐Diene Monomer Blends

ABSTRACT With a global shift toward energy sustainability, power cable insulation materials vital for modern energy transmission have seen needs for improvements. In this regard, thermoplastic polypropylene (PP) blends offer exceptional thermal and electrical properties over conventional insulation materials. Notably, nanostructuration of PP blends can further enhance the electrical properties of PP blends, but the underlying physics governing nanostructured PP blends has yet to be systematically explored. The current work therefore evaluates the effects of surface‐treated nanomagnesia (MgO) on the electro‐mechanical properties of PP blended with 10 wt%, 20 wt%, and 30 wt% of ethylene‐propylene‐diene monomer (EPDM). The results show that blending PP with EPDM exhibits significantly improved mechanical properties, with the elongation‐at‐break increasing beyond 400%, albeit that the breakdown strength deteriorates by 34%. Significantly, adding surface‐treated MgO to the PP/EPDM blends improves the breakdown strength of the materials by up to 14% without compromising the elongation‐at‐break of the materials. The mechanisms governing the improved breakdown strength of the PP/EPDM/MgO nanocomposites over the PP/EPDM blend counterparts are explained through changes in the materials' structures. These findings provide fundamental insights into the structure–property relationship of nanostructured PP blends crucial for the development of PP‐based power cable insulation.