Mechanical, thermal and tribological properties of polyimide/nano-SiO2 composites synthesized using an in-situ polymerization

Polyimide (PI)/nano-SiO 2 composites were successfully fabricated via a novel in-situ polymerization. Microstructure, thermal properties, mechanical performance and tribological behaviors of these composites were investigated. The results indicate that nano-SiO 2 dispersed homogeneously. Compared with pure PI, thermal stability and heat resistance are higher about 10   °C with the addition of 5   wt% nano-SiO 2 . Compressive strength and modulus of composite with 5   wt% nano-SiO 2 increase by 42.6 and 45.2%, respectively. The coefficient of friction (COF) of composite with 5   wt% nano-SiO 2 decrease by 6.8% owing to the thick and uniform transfer films. Excess nano-SiO 2 could adversely affect the COF of PI/nano-SiO 2 composite. Additionally, wear resistance deteriorates obviously since transfer film exfoliates easily and nano-SiO 2 aggregates on the surface of transfer films.