Enhancing high-temperature resistance and energy storage properties of polypropylene via grafting with glycidyl methacrylate

Conventional biaxially oriented polypropylene (PP) often suffers from elevated leakage current and reduced dielectric strength at high temperatures, preventing it from meeting the requirements for high-temperature-resistant, high-energy-density dielectric materials in advanced equipment, such as ultrahigh-voltage power transmission and new energy vehicles. This work proposes a strategy for grafting crosslinkable polar monomer glycidyl methacrylate (GMA) onto PP to improve its temperature resistance and energy storage performance. The introduction of GMA enhances the polarization capacity of PP and forms a crosslinked network structure within the matrix via the ring-opening reaction of epoxy groups, substantially strengthening intermolecular interactions and improving the mechanical and breakdown properties of PP. The modified PP exhibits a discharged energy density at 25 °C that is 60% higher than that of pure PP and maintains excellent stability even at 105 °C. The application of chemical grafting of crosslinkable functional monomers overcomes the limitations of traditional physical modification in terms of processing properties and provides a new approach to the fabrication of high-temperature-resistant, high-energy-storage all-organic dielectrics.