Tribological Properties of PTFE/PEI and Graphite/PEI Blends

The tribological performances of polyetherimide(PEI) composite materials filled with polytetrafluoroethylene( PTFE) and graphite were evaluated on UMT-2 friction and wear tester, respectively. The microstructures of worn surfaces, cross-sections of the PEI composite were examined with scanning electron microscope( SEM), and wear mechanism was analyzed. The result showed that PEI composite filled with PTFE and graphite were improved significantly on friction and wear properties. The friction coefficient is reduced to below 0.3 (the friction coefficient of pure PEI is 0. 41), the wear rate is reduced by 3 orders of magnitude. When filled with 10% PTFE in composites PTFE system, the friction coefficient of the composites is lowest, and the friction coefficient of the graphite counterpart is lowest in 15% graphite content. The lowest friction coefficient is 0. 23 and 0. 27. For the wear rate, PEI composite materials filled with PTFE and graphite are both decreased with the content increasing respectively. Consequently, compared with the PEI composite materials filled with graphite, the PEI composite materials filled with PTFE has more excellent tribological performance and mechanical behavior. The mechanical behavior of two kinds of the PEI composites was also measured, such as tensile strength, bending strength, impact strength and Rockwell hardness. The results show that, when the mass fraction of 5% 15%, which is the best tribological performance improvement in addition, comprehensive mechanical properties of blends of materials is still good.