Polytetrafluoroethylene/nanoclay composite as anti-wearing compound

Abstract

The most important application of polytetrafluoroethylene (PTFE) polymer in industry is its use as a solid lubricant, due to its lack of reactivity with most industrial materials. However, the PTFE polymer has low abrasive resistance that limited its usage. In this research, 0, 2, and 5% of nanoclay were added to PTFE polymer as filler, and properties of the resultant nanocomposites were investigated. For this purpose, the nanoclay was first dissolved in a solution of water and surfactant, and then added into the PTFE. After thoroughly mixing, the cylindrical specimens were produced by cold pressing and heated to 340 °C for 2 h in an atmosphere-protected furnace. EDS analysis, electron scanning microscopy and pin-on-disk wear test were done on nanocomposites. The results of the EDS proved the uniform distribution of nanoclay in the matrix of PTFE. The abrasion test showed that the wear resistance was more than 100 times in the nanocomposite containing 5% nanoclay than PTFE. The investigation of the abrasive particles showed that the particles separated from polymer are longer and thicker than those separated from nanocomposite. By observing the surface of the abrasive pin after the wear test, it became clear that the transfer film from the PTFE polymer was formed on the surface of the abrasive pin and prevented the nanocomposite from the abrasion directly. Therefore, the abrasion mechanism in nanocomposites is “abrasive” due to the surface adhesion.