Surface Modification of Nano-Al2O3 with Silane Coupling Agent and Its Effect on the Compressive Strength of PI/Al2O3 Composites

In this study, a series of nano-Al2O3 reinforced polyimide (PI) composites were fabricated using the hot compression method. A silane coupling agent was used to modify the surface of nano-Al2O3 powder to enhance the PI/Al2O3 interface compatibility. The effects of Al2O3 contents on the microstructures, thermal behavior and mechanical properties of PI/Al2O3 composites were investigated. The results suggested that chemical reactions occurred during in situ modification. The nano-Al2O3 was cross-linked to the PI matrix, which reduced the mobility of PI chains and improved the elastic modulus of the composites. When the Al2O3 content was 30 wt.%, the compressive strength of composites reached the maximum value of 313 MPa and increased by 26.5% than that of the PI matrix.