Investigations on the influence of polytetrafluoroethylene powder as a filler on physico-mechanical and wear characteristics of nylon 66/graphite composites

The objective of this research article is to evaluate the physico-mechanical and tribological properties of nylon 66 and polytetrafluoroethylene (PTFE) powder composites in the presence of graphite (Gr) particulate filler. Nylon 66 containing 2 wt% Gr powder was extruded with 5, 10, 15 and 20 wt% PTFE powder in a co-rotating twin-screw extruder. The fabricated nylon 66/Gr/PTFE composites have been evaluated for physico-mechanical properties, such as tensile behaviors, impact strength, water absorption, density and void content. The thermal characteristics of the composites have been studied by using dynamic mechanical analysis and thermogravimetric analysis. The effect of PTFE content, loads, sliding velocities and sliding distances on wear characteristics of the composites were evaluated using pin-on-disc equipment. The nylon 66/Gr/PTFE composites showed enhanced impact strength, thermal stability, wear resistance and reduced coefficient of friction. It was found that wear performance was greatly influenced by selected experimental parameters. Worn surfaces were examined with scanning electron microscopy to have better insight into the wear mechanism. It was observed that the PTFE played a main role in the tensile resistant and wear resistant properties of nylon 66 composites.