A synergistic effect of traphite 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 ar- rangement. 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 slid- ing speed, and showed better friction and wear behavior under oil lubrication and worse tribological properties under water lubrication.