A Synergistic Effect of Graphite and Nano-CuO on the Tribological Behavior of Polyimide Composites.

Polyimide (PI) composites modified with nano-CuO and graphite were prepared by means of a hot press molding technique. The effects of nano-CuO and graphite on the tribological properties of the composites were studied using a block-on-ring arrangement. The results revealed that the incorporation of graphite alone improved the friction-reducing and anti-wear abilities of the PI composites, whereas incorporation of nano-CuO alone deteriorated the wear resistance of the PI composite owing to its abrasive effect. A synergistic effect was found for the combination of nano-CuO and graphite, which leads to the best tribological properties. The results showed that the filled PI composites exhibited worse tribological properties under higher load and sliding speed, and showed better friction and wear behavior under oil lubrication and worse tribological properties under water lubrication. [ABSTRACT FROM AUTHOR]