Dielectric and thermal properties of nano Mg(OH)₂-ZnO/polyimide composite film

Nano Mg(OH)₂-Zn(OH)₂ particles were prepared by reverse precipitation method, nano Mg(OH)₂-ZnO/polyimide(PI) composite films with different mass contents of Mg(OH)₂-ZnO were successfully prepared by in-situ polymerization and thermal imidization. The surface morphology, thermal stability, dielectric properties and breakdown strength of the films were characterized by SEM, TG, dielectric spectrum tester and breakdown strength tester. The results show that the Mg(OH)₂-ZnO nanoparticles are homogeneously dispersed in the PI matrix, thermal stability decreases, dielectric constant, dielectric loss and electrical conductivity have been increased, the breakdown strength of nano Mg(OH)₂-ZnO/PI composite films increases first and then decreases with the increasing of nanoparticles, and reaches a maximum value of 296 kV/mm at nanoparticle content of 2%.