An investigation on enhancing the wear resistance of PTFE-based composites through complex fillers incorporating a combination of kaolinite and single-walled carbon nanotubes

Abstract

ABSTRACT In this study, the combined effect of kaolinite with single-walled carbon nanotubes (SWCNTs) on mechanical, tribological, thermodynamic properties and structure of polymer composites based on polytetrafluoroethylene was investigated. Combination of SWCNTs with the composite mixture (containing kaolinite) was carried out in liquid and dry forms by ultrasonic dispersion. X-ray diffraction analysis revealed that the composite with 0.5 wt.% SWCNTs and 1 wt.% kaolinite in the liquid treatment was characterized by a 12% increase in the degree of crystallinity. It is shown that the introduction of complex fillers into PTFE significantly increased the wear resistance of composites by 688 times compared to the initial PTFE. Mechanical testing of the composites showed an increase in elastic modulus by 29% and 28% increase in compressive strength compared to the initial PTFE. The friction surface of the composites was investigated using IR spectroscopy and scanning electron microscopy. It was registered that the PCM friction surface is characterized by the formation of “scaly” structures. The IR spectra of PCM friction surfaces revealed the presence of hydroxyl groups and carboxylate anions – perfluorocarboxylic acid. It indicates the formation of a new structure on the friction surfaces of the composites with the formation of “scaly” micro-protrusions at increasing SWCNTs concentration. Keywords: polytetrafluoroethylene; single-walled carbon nanotubes; kaolinite; ultrasonic treatment.