Reciprocating sliding of polyester textile fabric composites along different fabric orientations

The coefficients of friction and wear rates of thermoset polyester matrix composites with plain woven polyester fabric reinforcement were studied during reciprocating sliding under adhesive line contact at 50 to 200 N normal loads and 0.3 to 1.2 m/s sliding velocities. The samples were prepared along different orientations of the fabric relatively to the sliding surface and sliding directions, including 0°, 30°, 45°, 60° and 90° in-plane directions and thickness z direction. The coefficients of friction and wear rates were maximum along 90° and minimum along 45° for pure and polytetrafluoroethylene-filled composites. For the latter, overload conditions were minimized, and friction and wear became low for perpendicular fabric orientations. Although sliding is controlled by solid lubrication of polytetrafluoroethylene, the fiber orientations remain dominating the friction under mild sliding conditions. The differences between friction properties along weft and warp orientations could be correlated with mechanical properties along those directions. However, a systematic study in parallel with interpretation of the thermal heating could provide better insights in dry sliding properties. By considering the effects of thermal heating, thermo-mechanical sliding conditions in the interface controlled self-lubricating properties of polytetrafluoroethylene. The wear mechanisms along 0° and 90° directions were mainly determined by the fabric reinforcement, and the sliding along off-axis 45° and thickness directions was mainly controlled by the matrix and polytetrafluoroethylene deposits.