Abstract:
High temperature and dielectric constant polymer nanocomposites have attracted widespread attention in pulse power system such as mobile electronics, electric vehicles and electronic equipment due to their processing flexibility, light weight, and low cost. Herein, a new type of thermosetting benzoxazole high-temperature resistant resin, NPBO, was synthesized. The chemical structure and thermal curing behavior of NPBO were studied by H-NMR, EI-MS spectra and DSC. The resin exhibited excellent thermal properties. Meanwhile, a stepwise chemical grafting was performed to prepare polyurethane-coated barium titanate core-shell hybrid nanoparticles (PU@BT). Then, PU@BT and NPBO resins were hybridized at different ratios to produce PU@BT/NPBO nanocomposites. Using scanning electron microscope (SEM) and transmission electron microscope (TEM), the morphology of PU@BT was first characterized. The particles of PU@BT were found to be well dispersed. Finally, the dielectric properties of the composite were measured by a broadband dielectric spectrometer. As the volume fraction of PU@BT increased from 0 to 10%, the dielectric constant of the composite material increased significantly. At 1 kHz, the dielectric constant of NPBO was 3.3. When 10% PU@BT was added, the dielectric constant of the composite increased to 7.3.