Mechanical and tribological properties of polymer composite materials based on PTFE filled with natural mica and magnesium aluminium oxide

In this research, the results of studies on the influence of natural mica and mixed magnesium aluminium oxide (MAO) on the structure and properties of polytetrafluoroethylene (PTFE) are presented. Mechanical and tribological tests were conducted on PTFE-based composite samples. It was found that the addition of mica increases the relative elongation by 43 % and raises the wear resistance by 277 times compared to the initial polymer. The coefficient of friction is from 0.24 to 0.29. At the supplementary addition of mixed magnesium aluminium oxide, the wear resistance increases by up to 312 times and the coefficient of friction decreases by 38 %. It is shown that, with the addition of mica alone, the relative elongation improves and that with the additional introduction of mixed magnesium aluminium oxide, the wear resistance of the material increases. The maximum wear resistance is shown by the composite containing 5 wt. % mica and 1 wt. % MAO. Investigations of the worn surface of composites have shown that the decrease in mass loss of composites is associated with the formation of a wear resistant surface formed during the asperity interaction. It is revealed that the formation of a wear resistant structure on the material's contact surface is caused by the formation of a secondary layer and chemical reactions that occur during interaction.