Enabling High-Performance Polypropylene Nanocomposites With Interfacial Deep Traps

Polymer nanocomposites are the material of choice for dc insulation. The emerging demand for high-capacity high voltage direct current (HVdc) power transmission requires polymer nanocomposites capable of safe and stable operation at high temperatures. However, the high-temperature electrical properties of current polymer nanocomposites are still unsatisfactory. Here, we report that the modulation of polymer/nanoparticle interfaces can greatly improve the high-temperature insulation properties of polypropylene (PP)-based nanocomposite for recyclable HVdc cable insulation application. The nanoparticles are surface-modified with PP-graft-maleic anhydride (PP- ${g}$ -mah), which is not only well miscible with PP but also contains polar groups to act as interfacial deep traps. We demonstrate that the interfacial deep traps can improve the dc breakdown strength and the electrical resistivity of polymer nanocomposite by inhibiting the charge injection. This work deepens the understanding of interfacial effects in polymer nanocomposites and provides new opportunities for designing high-performance recyclable insulation materials for HVdc cables.