RETRACTED ARTICLE: Effects of Copper Nanoparticles Located in Different Regions of Polytetrafluoroethylene/Polyimide Blends on the Morphology, Mechanical and Tribological Properties of PTFE Composites

The effects of copper nanoparticles (Cu) located in different regions of polytetrafluoroethylene/polyimide (PTFE/PI) blends on the morphology, thermal, mechanical, and tribological properties of PTFE composites were studied. Region one is PI phases (the corresponding composites is denoted as PPC), region two is PTFE phases and the interface between PTFE and PI (the corresponding composites is denoted as PPC-m). Results indicate that the incorporation of Cu nanoparticles into PI phases improves the dispersibility and homogeneity of PI phases. As a consequence, the crystallinity of PTFE composites is reduced, but compressive strength and modulus of PTFE composites are enhanced by 50.3% and 14.4% respectively. In addition, self-lubricity and wear resistance of PTFE composites are improved by 10.4% and 50.5%. Scanning electron microscopy (SEM) demonstrates that PI phases with Cu nanoparticles hinder the direct contact between PTFE matrix and counterparts. However, Cu nanoparticles located in PTFE matrix and the interface between PTFE and PI deteriorates the dispersibility and homogeneity of PI phases, which lead to the poor mechanical and tribological performance of PTFE composites.