Improved High-Temperature Electrical Properties of Polymeric Material by Grafting Modification

Grafting modification is an effective method to enhance the electrical characteristics of polymeric materials by establishing deep traps that prevent carriers from being injected and transmitted. However, grafted polymers for electrical insulation suffer from large leakage current at elevated temperatures, limiting their application in harsh environments. We report that an itaconic anhydride grafted polypropylene synthesized by the solution grafting method preserves excellent insulating properties up to 120 °C. It is demonstrated that the grafted itaconic anhydride restrains free electrons employing strong electrostatic attraction and obstructs charge injection and transport. Furthermore, we reveal that strong intramolecular forces, deep energy traps, and fragmentized spherulites are essential factors contributing to grafted polymers' superior high-temperature electrical properties. This work provides insights into the sophisticated charge transport mechanisms in grafted polymers and their effects on the insulation characteristics, which is critical for the suitable design of polymeric materials with exceptional electrical properties.