Effect of KH550-modified Al2O3 on the properties of PI/Al2O3 composite films

In this paper, the surface of Al2O3 was modified with the different content of γ-aminopropyltriethoxyl silane. The obtained modified Al2O3 particles were characterized by spectroscopy(FT-IR) and X-ray diffraction(XRD). Results showed that KH550 was attached on the surface of Al2O3 particles successfully. And the Al2O3 particles and KH550-modified Al2O3 particles were added to the PI matrix, respectively, PI composite films with 16wt% of Al2O3 content were prepared with in-situ polymerization. The cross-section microstructure of the obtained composite films was characterized with scanning electron microscope (SEM). Results indicated that different contents of KH550 have a great influence on the dispersion of inorganic particles. In addition, the mechanical properties and breakdown field strength of the composite films were tested. Test results showed that when the content of KH550 was 2wt%, the tensile strength and elongation at break of PI/KH550-Al2O3 composite films were optimal and were 130 MPa, 12% respectively. Compared with the PI/Al2O3 films, the tensile strength and elongation at break of PI/KH550-Al2O3 composite films were increased by 22.8% and 44.5%, respectively. And the breakdown field strength of that was similar to PI/Al2O3 films.